Golf club face
Golf club heads are described comprising a striking surface that includes a center zone that is free of scorelines and an impact zone having an impact zone area, Aiz, and having a plurality of scorelines in the impact zone having an impact zone scoreline area, Asliz, such that a ratio Asliz/Aiz is at least 0.10.
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This application is a continuation-in-part of U.S. patent application Ser. No. 13/111,715, filed May 19, 2011, which is a continuation-in-part of U.S. patent application Ser. No. 11/960,609, filed Dec. 19, 2007, each of which is incorporated herein by reference.
FIELDThis disclosure pertains generally to composite articles. Particularly, the disclosure pertains to golf clubs and club-heads that have a composite face insert, and more particularly, composite face inserts having certain impact surface textures.
BACKGROUNDWith the ever-increasing popularity and competitiveness of golf, substantial effort and resources are currently being expended to improve golf clubs so that increasingly more golfers can have more enjoyment and more success at playing golf. Much of this improvement activity has been in the realms of sophisticated materials and club-head engineering. For example, modern “wood-type” golf clubs (notably, “drivers,” “fairway woods,” and “utility clubs”), with their sophisticated shafts and non-wooden club-heads, bear little resemblance to the “wood” drivers, low-loft long-irons, and higher numbered fairway woods used years ago. These modern wood-type clubs are generally called “metal-woods.”
An exemplary metal-wood golf club such as a fairway wood or driver typically includes a hollow shaft having a lower end to which the club-head is attached. Most modern versions of these club-heads are made, at least in part, of a light-weight but strong metal such as titanium alloy. The club-head comprises a body to which a strike plate (also called a face plate) is attached or integrally formed. The strike plate defines a front surface or strike face that actually contacts the golf ball.
The current ability to fashion metal-wood club-heads of strong, light-weight metals and other materials has allowed the club-heads to be made hollow. Use of materials of high strength and high fracture toughness has also allowed club-head walls to be made thinner, which has allowed increases in club-head size, compared to earlier club-heads. Larger club-heads tend to provide a larger “sweet spot” on the strike plate and to have higher club-head inertia, thereby making the club-heads more “forgiving” than smaller club-heads. Characteristics such as size of the sweet spot are determined by many variables including the shape profile, size, and thickness of the strike plate as well as the location of the center of gravity (CG) of the club-head.
The distribution of mass around the club-head typically is characterized by parameters such as rotational moment of inertia (MOI) and CG location. Club-heads typically have multiple rotational MOIs, each associated with a respective Cartesian reference axis (x, y, z) of the club-head. A rotational MOI is a measure of the club-head's resistance to angular acceleration (twisting or rotation) about the respective reference axis. The rotational MOIs are related to, inter alia, the distribution of mass in the club-head with respect to the respective reference axes. Each of the rotational MOIs desirably is maximized as much as practicable to provide the club-head with more forgiveness.
Another factor in modern club-head design is the face plate. Impact of the face plate with the golf ball results in some rearward instantaneous deflection of the face plate. This deflection and the subsequent recoil of the face plate are expressed as the club-head's coefficient of restitution (COR). A thinner face plate deflects more at impact with a golf ball and potentially can impart more energy and thus a higher rebound velocity to the struck ball than a thicker or more rigid face plate. Because of the importance of this effect, the COR of clubs is limited under United States Golf Association (USGA) rules.
Regarding the total mass of the club-head as the club-head's mass budget, at least some of the mass budget must be dedicated to providing adequate strength and structural support for the club-head. This is termed “structural” mass. Any mass remaining in the budget is called “discretionary” or “performance” mass, which can be distributed within the club-head to address performance issues, for example.
Some current approaches to reducing structural mass of a club-head are directed to making at least a portion of the club-head of an alternative material. Whereas the bodies and face plates of most current metal-woods are made of titanium alloy, several “hybrid” club-heads are available that are made, at least in part, of components formed from both graphite/epoxy-composite (or another suitable composite material) and a metal alloy. For example, in one group of these hybrid club-heads a portion of the body is made of carbon-fiber (graphite)/epoxy composite and a titanium alloy is used as the primary face-plate material. Other club-heads are made entirely of one or more composite materials. Graphite composites have a density of approximately 1.5 g/cm3, compared to titanium alloy which has a density of 4.5 g/cm3, which offers tantalizing prospects of providing more discretionary mass in the club-head.
Composite materials that are useful for making club-head components comprise a fiber portion and a resin portion. In general the resin portion serves as a “matrix” in which the fibers are embedded in a defined manner. In a composite material for club-heads, the fiber portion is configured as multiple fibrous layers or plies that are impregnated with the resin component. The fibers in each layer have a respective orientation, which is typically different from one layer to the next and precisely controlled. The usual number of layers is substantial, e.g., fifty or more. During fabrication of the composite material, the layers (each comprising respectively oriented fibers impregnated in uncured or partially cured resin; each such layer being called a “prepreg” layer) are placed superposedly in a “lay-up” manner. After forming the prepreg lay-up, the resin is cured to a rigid condition.
Conventional processes by which fiber-resin composites are fabricated into club-head components utilize high (and sometimes constant) pressure and temperature to cure the resin portion in a minimal period of time. The processes desirably yield components that are, or nearly are, “net-shape,” by which is meant that the components as formed have their desired final configurations and dimensions. Making a component at or near net-shape tends to reduce cycle time for making the components and to reduce finishing costs. Unfortunately, at least three main defects are associated with components made in this conventional fashion: (a) the components exhibit a high incidence of composite porosity (voids formed by trapped air bubbles or as a result of the released gases during a chemical reaction); (b) a relatively high loss of resin occurs during fabrication of the components; and (c) the fiber layers tend to have “wavy” fibers instead of straight fibers. Whereas some of these defects may not cause significant adverse effects on the service performance of the components when the components are subjected to simple (and static) tension, compression, and/or bending, component performance typically will be drastically reduced whenever these components are subjected to complex loads, such as dynamic and repetitive loads (i.e., repetitive impact and consequent fatigue).
Manufacturers of metal wood golf club-heads have more recently attempted to manipulate the performance of their club heads by designing what is generically termed a variable face thickness profile for the striking face. It is known to fabricate a variable-thickness composite striking plate by first forming a lay-up of prepreg plies, as described above, and then adding additional “partial” layers or plies that are smaller than the overall size of the plate in the areas where additional thickness is desired (referred to as the “partial ply” method). For example, to form a projection on the rear surface of a composite plate, a series of annular plies, gradually decreasing in size, are added to the lay-up of prepreg plies.
Unfortunately, variable-thickness composite plates manufactured using the partial ply method are susceptible to a high incidence of composite porosity because air bubbles tend to remain at the edges of the partial plies (within the impact zone of the plate). Moreover, the reinforcing fibers in the prepreg plies are ineffective at their ends. The ends of the fibers of the partial plies within the impact zone are stress concentrations, which can lead to premature delamination and/or cracking. Furthermore, the partial plies can inhibit the steady outward flow of resin during the curing process, leading to resin-rich regions in the plate. Resin-rich regions tend to reduce the efficacy of the fiber reinforcement, particularly since the force resulting from golf-ball impact is generally transverse to the orientation of the fibers of the fiber reinforcement.
Typically, conventional CNC machining is used during the manufacture of composite face plates, such as for trimming a cured part. Because the tool applies a lateral cutting force to the part (against the peripheral edge of the part), it has been found that such trimming can pull fibers or portions thereof out of their plies and/or induce horizontal cracks on the peripheral edge of the part. As can be appreciated, these defects can cause premature delamination and/or other failure of the part.
While durability limits the application of non-metals in striking plates, even durable plastics and composites exhibit some additional deficiencies. Conventional metallic striking plates include a fine ground striking surface (and may include a series of horizontal grooves for some metalwoods and most all irons) that tends to promote a preferred ball spin in play under wet conditions. This fine ground surface appears to provide a relief volume for water present at a striking surface/ball impact area so that impact under wet conditions produces a ball trajectory and shot characteristics similar to those obtained under dry conditions. While non-metals suitable for striking plates are durable, these materials generally do not provide a durable roughened, grooved, or textured striking surface such as provided by conventional clubs and that is needed to maintain club performance under various playing conditions. Accordingly, improved striking plates, striking surfaces, and golf clubs that include such striking plates and surfaces and associated methods are needed.
SUMMARYSome disclosed examples pertain to composite articles, and in particular a composite face plate for a golf club-head, and methods for making the same. In certain embodiments, a composite face plate for a club-head is formed with a cross-sectional profile having a varying thickness. The face plate comprises a lay-up of multiple, composite prepreg plies. The face plate can include additional components, such as an outer polymeric or metal layer (also referred to as a cap) covering the outer surface of the lay-up and forming the striking surface of the face plate. In other embodiments, the outer surface of the lay-up can be the striking surface that contacts a golf ball upon impact with the face plate.
In order to vary the thickness of the lay-up, some of the prepreg plies comprise elongated strips of prepreg material arranged in a crisscross, overlapping pattern so as to add thickness to the composite lay-up in one or more regions where the strips overlap each other. The strips of prepreg plies can be arranged relative to each other in a predetermined manner to achieve a desired cross-sectional profile for the face plate. For example, in one embodiment, the strips can be arranged in one or more clusters having a central region where the strips overlap each other. The lay-up has a projection or bump formed by the central overlapping region of the strips and desirably centered on the sweet spot of the face plate. A relatively thinner peripheral portion of the lay-up surrounds the projection. In another embodiment, the lay-up can include strips of prepreg plies that are arranged to form an annular projection surrounding a relatively thinner central region of the face plate, thereby forming a cross-sectional profile that is reminiscent of a “volcano.”
The strips of prepreg material desirably extend continuously across the finished composite part; that is, the ends of the strips are at the peripheral edge of the finished composite part. In this manner, the longitudinally extending reinforcing fibers of the strips also extend continuously across the finished composite part such that the ends of the fibers are at the periphery of the part. In addition, the lay-up can initially be formed as an “oversized” part in which the reinforcing fibers of the prepreg material extend into a peripheral sacrificial portion of the lay-up. Consequently, the curing process for the lay-up can be controlled to shift defects into the sacrificial portion of the lay-up, which subsequently can be removed to provide a finished part with little or no defects. Moreover, the durability of the finished part is increased because the free ends of the fibers are at the periphery of the finished part, away from the impact zone.
The sacrificial portion desirably is trimmed from the lay-up using water-jet cutting. In water jet cutting, the cutting force is applied in a direction perpendicular to the prepreg plies (in a direction normal to the front and rear surfaces of the lay-up), which minimizes damage to the reinforcing fibers.
In one representative embodiment, a golf club-head comprises a body having a crown, a heel, a toe, and a sole, and defining a front opening. The head also includes a variable-thickness face insert closing the front opening of the body. The insert comprises a lay-up of multiple, composite prepreg plies, wherein at least a portion of the plies comprise a plurality of elongated prepreg strips arranged in a criss-cross pattern defining an overlapping region where the strips overlap each other. The lay-up has a first thickness at a location spaced from the overlapping region and a second thickness at the overlapping region, the second thickness being greater than the first thickness.
In another representative embodiment, a golf club-head comprises a body having a crown, a heel, a toe, and a sole, and defining a front opening. The head also includes a variable-thickness face insert closing the front opening of the body. The insert comprises a lay-up of multiple, composite prepreg plies, the lay-up having a front surface, a peripheral edge surrounding the front surface, and a width. At least a portion of the plies comprise elongated strips that are narrower than the width of the lay-up and extend continuously across the front surface. The strips are arranged within the lay-up so as to define a cross-sectional profile having a varying thickness.
In another representative embodiment, a composite face plate for a club-head of a golf club comprises a composite lay-up comprising multiple prepreg layers, each prepreg layer comprising at least one resin-impregnated layer of longitudinally extending fibers at a respective orientation. The lay-up has an outer peripheral edge defining an overall size and shape of the lay-up. At least a portion of the layers comprises a plurality of composite panels, each panel comprising a set of one or more prepreg layers, each prepreg layer in the panels having a size and shape that is the same as the overall size and shape of the lay-up. Another portion of the layers comprises a plurality of sets of elongated strips, the sets of strips being interspersed between the panels within the lay-up. The strips extend continuously from respective first locations on the peripheral edge to respective second locations on the peripheral edge and define one or more areas of increased thickness of the lay-up where the strips overlap within the lay-up.
In another representative embodiment, a method for making a composite face plate for a club-head of a golf club comprises forming a lay-up of multiple prepreg composite plies, a portion of the plies comprising elongated strips arranged in a criss-cross pattern defining one or more areas of increased thickness in the lay-up where one or more of the strips overlap each other. The method can further include at least partially curing the lay-up, and shaping the at least partially cured lay-up to form a part having specified dimensions and shape for use as a face plate or part of a face plate for a club-head.
In still another representative embodiment, a method for making a composite face plate for a club-head of a golf club comprises forming a lay-up of multiple prepreg plies, each prepreg ply comprising at least one layer of reinforcing fibers impregnated with a resin. The method can further include at least partially curing the lay-up, and water jet cutting the at least partially cured lay-up to form a composite part having specified dimensions and shape for use as a face plate or part of a face plate in a club-head.
In some examples, golf club heads comprise a club body and a striking plate secured to the club body. The striking plate includes a face plate and a cover plate secured to the face plate and defining a striking surface, wherein the striking surface includes a plurality of scoreline indentations. In some examples, an adhesive layer secures the cover plate to the face plate. In other alternative embodiments, the scoreline indentations are at least partially filled with a pigment selected to contrast with an appearance of an impact area of the striking surface and the cover plate is metallic and has a thickness between about 0.25 mm and 0.35 mm. In further examples, the scoreline indentations are between about 0.05 and 0.09 mm deep. In other representative examples, a ratio of a scoreline indentation width to a cover plate thickness is between about 2.5 and 3.5, and the face plate is formed of a titanium alloy. In some examples, the scoreline indentations include transition regions having radii of between about 0.2 mm and 0.6 mm, and the cover plate includes a rim configured to extend around a perimeter of the face plate. According to some embodiments, the face plate is a composite face plate and the club body is a wood-type club body.
Cover plates for a golf club face plate comprise a titanium alloy sheet having bulge and roll curvatures, and including a plurality of scoreline indentations. A scoreline indentation depth D is between about 0.05 mm and 0.12 mm, and a titanium alloy sheet thickness T is between about 0.20 mm and 0.40 mm.
In further examples, golf club heads comprise a club body and a striking plate secured to the club body. The striking plate includes a metallic cover having a plurality of impact resistant scoreline indentations situated on a striking surface. In some examples, the metallic cover is between about 0.2 mm and 1.0 mm thick and the scoreline indentations have depths between about 0.1 mm and 0.02 mm. In further examples, the scoreline indentations have a depth D and the metallic cover has a thickness T such that a ratio D/T is between about 0.15 and 0.30 or between about 0.20 and 0.25. In additional examples, the face plate is a variable thickness face plate.
Methods comprise selecting a metallic cover sheet and trimming the metallic cover sheet so as to conform to a golf club face plate. The metallic cover sheet provides a striking surface for a golf club. A plurality of scoreline indentations are defined in the striking surface, wherein the metallic cover sheet has a thickness T between about 0.1 mm and 0.5 mm, and the scoreline indentations have a depth D such that a ratio D/T is between about 0.1 and 0.4. In additional examples, a rim is formed on the cover sheet and is configured to cover a perimeter of the face plate. In typical examples, the metallic sheet is a titanium alloy sheet and is trimmed after formation of the scoreline indentations. In some examples, the scoreline indentations are formed in an impact area of the striking surface or outside of an impact area of the striking surface.
According to some examples, golf club heads (wood-type or iron-type) comprise a club body and a striking plate secured to the club body. The striking plate includes a composite face plate having a front surface and a polymer cover layer secured to the front surface of the face plate, the polymer cover layer having a textured striking surface. In some embodiments, a thickness of the cover layer is between about 0.1 mm and about 2.0 mm or about 0.2 mm and 1.2 mm, or the thickness of the cover layer is about 0.4 mm. In further examples, the striking face of the composite face plate has an effective Shore D hardness of at least about 75, 80, or 85. In additional representative examples, the textured striking surface has one or more of a mean surface roughness between about 1 μm and 10 μm, a mean surface feature frequency of at least about 2/mm, or a surface profile kurtosis greater than about 1.5, 1.75, or 2.0. In additional embodiments, the textured striking surface has a mean surface roughness of less than about 4.5 μm, a mean surface feature frequency of at least about 3/mm, and a surface profile kurtosis greater than about 2 as measured in a top-to-bottom direction, a toe-to-heel direction, or along both directions. In some examples, the striking surface is textured along a top-to-bottom direction or a toe-to-heel direction only. In other examples, the striking surface is textured along an axis that is tilted with respect to a toe-to-heel and a top-to-bottom direction.
Methods comprise providing a face plate for a golf club and a cover layer for a front surface of the face plate. A striking surface of the cover layer is patterned so as to provide a roughened or textured striking surface. According to some examples, the roughened striking surface is patterned to include a periodic array of surface features that provide a mean roughness less than about 5 μm and a mean surface feature frequency along at least one axis substantially parallel to the striking surface of at least 2/mm. In other examples, the striking surface of the cover layer is patterned with a mold. In further examples, the striking surface is patterned by pressing a fabric against the cover layer, and subsequently removing the fabric. In a representative example, the cover layer is formed of a thermoplastic and the fabric is applied as the cover layer is formed.
Golf club heads comprise a face plate having a front surface and a control layer situated on the front surface of the face plate, wherein the control layer has a striking surface having a surface roughness configured to provide a ball spin similar to a conventional metal face under wet conditions. In some examples, the control layer is a polymer layer. In further examples, the control layer is a polymer layer having a thickness of between about 0.3 mm and 0.5 mm, and the surface roughness of the striking surface is substantially periodic along at least one axis that is substantially parallel to the striking surface. In a representative examples, the striking surface of the face plate has a Shore D hardness of at least about 75, 80, or more preferably, at least about 85. The polymer layer can be a thermoset or thermoplastic material. In representative examples, the polymer layer is a SURLYN ionomer or similar material, or a urethane, preferably a non-yellowing urethane.
Also disclosed herein is a golf club head comprising a roughened striking surface that includes a surface profile having at least one peak, at least one valley, and a transition segment between the peak and the valley, wherein the at least one peak, the at least one valley, and the transition segment together define a mean line, and a substantial portion of the transition segment is near to, or on, the mean line. According to another embodiment, there is disclosed herein a golf club head comprising a roughened striking surface that defines a machined surface profile having a predetermined ratio of Ry/Ra that minimizes Ra while maintaining Ry. Also disclosed herein are methods for making golf clubs having the above-described striking surfaces.
Also disclosed are golf club heads having a ball-striking surface comprising an asymmetric surface texture, and related methods for making the same.
In further examples, golf club heads are provided having a body that includes a crown, a sole, a heel, and a toe, with the body defining an internal cavity having a front opening. A striking plate is attached to the body at the front opening, with the striking plate comprising a composite face plate having a front surface and a cover layer attached to the front surface of the face plate. The cover layer defines a forward facing striking surface having a peripheral edge, a center zone, an impact zone, and a peripheral zone. In several of the foregoing examples, the club head defines a striking surface area of at least 4,000 mm2, such as at least 5,000 mm2.
The center zone has no scorelines, and is defined by an outer border constituting a center zone circle having a diameter Dcz, with the center of the center zone circle corresponding with a USGA center face location. The center zone circle diameter Dcz is between 1 mm to 10 mm, such as between 3 mm to 8 mm, such as between 3 mm to 6 mm. The impact zone surrounds but does not include the center zone and is defined by an outer border constituting a rectangle having its center at the USGA center face location and having upper and lower sides aligned parallel to an address position ground plane and heel and toe sides aligned perpendicular to the address position ground plane, with the upper and lower sides each having a length of 45 mm and the heel and toe sides each having a length of 30 mm. The impact zone has an impact zone area, Aiz. The impact zone is provided with a plurality of scorelines having a scoreline area, Asliz, such that the ratio Asliz/Aiz is at least 0.10, such as at least 0.17, or such as at least 0.20. The peripheral zone surrounds but does not include the impact zone and extends to the peripheral edge, with the peripheral zone having a peripheral zone area, Apz.
In some examples, the peripheral zone is provided with a plurality of scorelines having a scoreline area, Aslpz, such that the ratio Aslpz/Apz is at least 0.10, such as at least 0.17, or such as at least 0.20.
In some examples, the cover layer has an average thickness of between 0.2 mm to 0.75 mm throughout at least the center zone and impact zone, and a plurality of scorelines in the impact zone have an average depth that is between 0.1 mm and 0.4 mm. In some further examples, a ratio of the average depth of the plurality of scorelines in the impact zone to the average thickness of the cover layer in the impact zone is between 0.2 to 0.9, such as between 0.5 to 0.8, or such as between 0.6 to 0.8.
In some examples, a ratio of the scoreline width to the width of the land area between adjacent scorelines is between 1:3 and 1:5, such as between 1:3 and 1:4, for at least 50% of the scorelines in the impact zone. In other examples, the ratio of the scoreline width to the width of the land area between adjacent scorelines is between 1:3 and 1:5, such as between 1:3 and 1:4, for at least 75% of the scorelines in the impact zone. In still other examples, a ratio of the scoreline width to the width of the land area between adjacent scorelines is between 1:3 and 1:5, such as between 1:3 and 1:4, for at least 50% of the scorelines in the peripheral zone. In still other examples, the ratio of the scoreline width to the width of the land area between adjacent scorelines is between 1:3 and 1:5, such as between 1:3 and 1:4, for at least 75% of the scorelines in the peripheral zone.
The foregoing and other objects, features, and advantages of the invention will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures.
This disclosure is set forth in the context of representative embodiments that are not intended to be limiting in any way.
In the following description, certain terms may be used such as “up,” “down,” “upper,” “lower,” “horizontal,” “vertical,” “left,” “right,” and the like. These terms are used, where applicable, to provide some clarity of description when dealing with relative relationships. But, these terms are not intended to imply absolute relationships, positions, and/or orientations. For example, with respect to an object, an “upper” surface can become a “lower” surface simply by turning the object over. Nevertheless, it is still the same object.
As used herein, the singular forms “a,” “an,” and “the” refer to one or more than one, unless the context clearly dictates otherwise.
As used herein, the term “includes” means “comprises.” For example, a device that includes or comprises A and B contains A and B but may optionally contain C or other components other than A and B. A device that includes or comprises A or B may contain A or B or A and B, and optionally one or more other components such as C.
As used herein, the term “composite” or “composite materials” means a fiber-reinforced polymeric material.
The main features of an exemplary hollow “metal-wood” club-head 10 are depicted in
In a club-head according to one embodiment, at least a portion of the face plate 12 is made of a composite including multiple plies or layers of a fibrous material (e.g., graphite, or carbon, fiber) embedded in a cured resin (e.g., epoxy). For example, the face plate 12 can comprise a composite component (e.g., component 40 shown in
An exemplary thickness range of the composite portion of the face plate is 7.0 mm or less. The composite desirably is configured to have a relatively consistent distribution of reinforcement fibers across a cross-section of its thickness to facilitate efficient distribution of impact forces and overall durability. In addition, the thickness of the face plate 12 can be varied in certain areas to achieve different performance characteristics and/or improve the durability of the club-head. The face plate 12 can be formed with any of various cross-sectional profiles, depending on the club-head's desired durability and overall performance, by selectively placing multiple strips of composite material in a predetermined manner in a composite lay-up to form a desired profile.
Attaching the face plate 12 to the support 18 of the club-head body 14 may be achieved using an appropriate adhesive (typically an epoxy adhesive or a film adhesive). To prevent peel and delamination failure at the junction of an all-composite face plate with the body of the club-head, the composite face plate can be recessed from or can be substantially flush with the plane of the forward surface of the metal body at the junction. Desirably, the face plate is sufficiently recessed so that the ends of the reinforcing fibers in the composite component are not exposed.
The composite portion of the face plate is made as a lay-up of multiple prepreg plies. For the plies the fiber reinforcement and resin are selected in view of the club-head's desired durability and overall performance. In order to vary the thickness of the lay-up, some of the prepreg plies comprise elongated strips of prepreg material arranged in one or more sets of strips. The strips in each set are arranged in a criss-cross, overlapping pattern so as to add thickness to the composite lay-up in the region where the strips overlap each other, as further described in greater detail below. The strips desirably extend continuously across the finished composite part; that is, the ends of the strips are at the peripheral edge of the finished composite part. In this manner, the longitudinally extending reinforcing fibers of the strips also can extend continuously across the finished composite part such that the ends of the fibers are at the periphery of the part. Consequently, during the curing process, defects can be shifted toward a peripheral sacrificial portion of the composite lay-up, which sacrificial portion subsequently can be removed to provide a finished part with little or no defects. Moreover, the durability of the finished part is increased because the free ends of the fibers are at the periphery of the finished part, away from the impact zone.
In tests involving certain club-head configurations, composite portions formed of prepreg plies having a relatively low fiber areal weight (FAW) have been found to provide superior attributes in several areas, such as impact resistance, durability, and overall club performance. (FAW is the weight of the fiber portion of a given quantity of prepreg, in units of g/m2.) FAW values below 100 g/m2, and more desirably below 70 g/m2, can be particularly effective. A particularly suitable fibrous material for use in making prepreg plies is carbon fiber, as noted. More than one fibrous material can be used. In other embodiments, however, prepreg plies having FAW values above 100 g/m2 may be used.
In particular embodiments, multiple low-FAW prepreg plies can be stacked and still have a relatively uniform distribution of fiber across the thickness of the stacked plies. In contrast, at comparable resin-content (R/C, in units of percent) levels, stacked plies of prepreg materials having a higher FAW tend to have more significant resin-rich regions, particularly at the interfaces of adjacent plies, than stacked plies of low-FAW materials. Resin-rich regions tend to reduce the efficacy of the fiber reinforcement, particularly since the force resulting from golf-ball impact is generally transverse to the orientation of the fibers of the fiber reinforcement.
In certain embodiments, the composite component 40 is fabricated by first forming an oversized lay-up of multiple prepreg plies, and then machining a sacrificial portion from the cured lay-up to form the finished part 40.
As shown in
In particular embodiments, the number of panels 52a-52k can range from 9 to 14 (with eleven panels 52a-52k being used in the illustrated embodiment) and the number of clusters 54a-54g can range from 1 to 12 (with seven clusters 54a-54g being used in the illustrated embodiment). However, in alternative embodiments, the number of panels and clusters can be varied depending on the desired profile and thickness of the part.
The prepreg plies used to form the panels 52a-52k and the clusters 54a-54g desirably comprise carbon fibers impregnated with a suitable resin, such as epoxy. An example carbon fiber is “34-700” carbon fiber (available from Grafil, Sacramento, Calif.), having a tensile modulus of 234 GPa (34 Msi) and a tensile strength of 4500 MPa (650 Ksi). Another Grafil fiber that can be used is “TR50S” carbon fiber, which has a tensile modulus of 240 GPa (35 Msi) and a tensile strength of 4900 MPa (710 ksi). Suitable epoxy resins are types “301” and “350” (available from Newport Adhesives and Composites, Irvine, Calif.). An exemplary resin content (R/C) is 40%.
The lay-up illustrated in
The strips 56a-56g in the illustrated embodiment are of equal length and are arranged such that the geometric center point 62 of the cluster corresponds to the center of each strip. The first three strips 56a-56c in this example have a width w1 that is greater than the width w2 of the last four strips 56d-56g. The strips define an angle α between the “horizontal” edges of the second strip 56b and the adjacent edges of strips 56a and 56c, an angle μ between the edges of strip 56b and the closest edges of strips 56d and 56g, and an angle θ between the edges of strip 56b and the closest edges of strips 56e and 56f. In a working embodiment, the width w1 is about 20 mm, the width w2 is about 15 mm, the angle α is about 24 degrees, the angle μ is about 54 degrees, and the angle θ is about 78 degrees.
Referring again to
When stacked in the lay-up, the overlapping regions 60 of the clusters are aligned in the direction of the thickness of the lay-up to increase the thickness of the central region 46 of the part 40 (
To form the lay-up, according to one specific approach, formation of the panels 52a-52k may be done first by stacking individual precut, prepreg plies 58a-58d of each panel. After the panels are formed, the lay-up is built up by laying the second panel 52b on top of the first panel 52a, and then forming the first cluster 54a on top of the second panel 52b by laying individual strips 56a-56g in the prescribed manner. The remaining panels 52c-52k and clusters 54b-54g are then added to the lay-up in the sequence shown in
The fully-formed lay-up can then be subjected to a “debulking” or compaction step (e.g., using a vacuum table) to remove and/or reduce air trapped between plies. The lay-up can then be cured in a mold that is shaped to provide the desired bulge and roll of the face plate. An exemplary curing process is described in detail below. Alternatively, any desired bulge and roll of the face plate may be formed during one or more debulking or compaction steps performed prior to curing. To form the bulge or roll, the debulking step can be performed against a die panel having the final desired bulge and roll. In either case, following curing, the cured lay-up is removed from the mold and machined to form the part 40.
The following aspects desirably are controlled to provide composite components that are capable of withstanding impacts and fatigue loadings normally encountered by a club-head, especially by the face plate of the club-head. These three aspects are: (a) adequate resin content; (b) fiber straightness; and (c) very low porosity in the finished composite. These aspects can be controlled by controlling the flow of resin during curing, particularly in a manner that minimizes entrapment of air in and between the prepreg layers. Air entrapment is difficult to avoid during laying up of prepreg layers. However, air entrapment can be substantially minimized by, according to various embodiments disclosed herein, imparting a slow, steady flow of resin for a defined length of time during the laying-up to purge away at least most of the air that otherwise would become occluded in the lay-up. The resin flow should be sufficiently slow and steady to retain an adequate amount of resin in each layer for adequate inter-layer bonding while preserving the respective orientations of the fibers (at different respective angles) in the layers. Slow and steady resin flow also allows the fibers in each ply to remain straight at their respective orientations, thereby preventing the “wavy fiber” phenomenon. Generally, a wavy fiber has an orientation that varies significantly from its naturally projected direction.
As noted above, the prepreg strips 56 desirably are of sufficient length such that the fibers in the strips extend continuously across the part 40; that is, the ends of each fiber are located at respective locations on the outer peripheral edge 49 of the part 40 (
In working examples, parts have been made without any voids, or entrapped air, and with a single void in one of the prepreg plies of the lay-up (either a strip or a panel-size ply). Parts in which there is a single void having its largest dimension equal to the thickness of a ply (about 0.1 mm) have a void content, or porosity, of about 1.7×10−6 percent or less by volume.
As the tool temperature increases from Ti to Ts, the viscosity of the resin first decreases to a minimum, at time t1, before the viscosity rises again due to cross-linking of the resin (
Curing continues after time t2 and follows a schedule of relatively constant temperature Ts and constant pressure P2. Note that resin viscosity exhibits some continued increase (typically to approximately 90% of maximum) during this phase of curing. This curing (also called “pre-cure”) ends at time t3 at which the component is deemed to have sufficient rigidity (approximately 90% of maximum) and strength for handling and removal from the tool, although the resin may not yet have reached a “full-cure” state (at which the resin exhibits maximum viscosity). A post-processing step typically follows, in which the components reach a “full cure” in a batch heating mode or other suitable manner.
Thus, important parameters of this specific process are: (a) Ts, the tool-set temperature (or typical resin-cure temperature), established according to manufacturer's instructions; (b) Ts, the initial tool temperature, usually set at approximately 50% of Ts (in ° F. or ° C.) to allow an adequate time span (t2) between Ti and Ts and to provide manufacturing efficiency; (c) P1, the initial pressure that is generally slightly higher than atmospheric pressure and sufficient to hold the component geometry but not sufficient to “squeeze” resin out, in the range of 20-50 psig for example; (d) P2, the ultimate pressure that is sufficiently high to ensure dimensional accuracy of components, in the range of 200-300 psig for example; (e) t1, which is the time at which the resin exhibits a minimal viscosity, a function of resin properties and usually determined by experiment, for most resins generally in the range of 5-10 minutes after first forming the lay-up; (f) t2, the time of maximum pressure, also a time delay from t1, where resin viscosity increases from minimum to approximately 80% of a maximum viscosity (i.e., viscosity of fully cured resin), appears to be related to the moment when the tool reaches Ts; and (g) t3, the time at the end of the pre-cure cycle, at which the components have reached handling strength and resin viscosity is approximately 90% of its maximum.
Many variations of this process also can be designed and may work equally as well. Specifically, all seven parameters mentioned above can be expressed in terms of ranges instead of specific quantities. In this sense, the processing parameters can be expressed as follows (see
Ts: recommended resin cure temperature ±ΔT, where ΔT=20, 50, 75° F.
Ti: initial tool temperature (or Ts/2)±ΔT.
P1: 0-100 psig±ΔP, where ΔP=5, 10, 15, 25, 35, 50 psi.
P2: 200-500 psig±ΔP.
t1: t (minimum±Δx viscosity)±Δt, where Δx=1, 2, 5, 10, 25% and Δt=1, 2, 5, 10 min.
t2: t (80%±Δx maximum viscosity)±Δt.
t3: t (90%±Δx maximum viscosity)±Δt.
After reaching full-cure, the components are subjected to manufacturing techniques (machining, forming, etc.) that achieve the specified final dimensions, size, contours, etc., of the components for use as face plates on club-heads. Conventional CNC trimming can be used to remove the sacrificial portion of the fully-cured lay-up (e.g., the portion surrounding line 64 in
In certain embodiments, the sacrificial portion of the fully-cured lay-up is removed by water jet cutting. In water-jet cutting, the cutting force is applied in a direction perpendicular to the prepreg plies (in a direction normal to the front and rear surfaces of the lay-up), which minimizes the occurrence of cracking and fiber pull out. Consequently, water-jet cutting can be used to increase the overall durability of the part.
The potential mass “savings” obtained from fabricating at least a portion of the face plate of composite, as described above, is about 10-30 g, or more, relative to a 2.7-mm thick face plate formed from a titanium alloy such as Ti-6Al-4V, for example. In a specific example, a mass savings of about 15 g relative to a 2.7-mm thick face plate formed from a titanium alloy such as Ti-6Al-4V can be realized. As mentioned above, this mass can be allocated to other areas of the club, as desired.
The embodiments described thus far provide a face plate having a projection or cone at the sweet spot. However, various other cross-sectional profiles can be achieved by selective placement of prepreg strips in the lay-up.
Each cluster 114a-114c in this embodiment comprises four criss-cross strips 116 arranged in a specific shape. In the illustrated embodiment, the strips of the first cluster 114a are arranged to form a parallelogram centered on the center of the panel 112a. The strips of the second cluster 114b also are arranged to form a parallelogram centered on the center of the panel 112b and rotated 90 degrees with respect to the first cluster 114a. The strips of the third cluster 114c are arranged to form a rectangle centered on the center of panel 112c. When stacked in the lay-up, as best shown in
It can be appreciated that the number of strips in each cluster can vary and still form the same profile. For example, in another embodiment, clusters 114a-114c can be stacked immediately adjacent each other between adjacent panels 112 (i.e., effectively forming one cluster of twelve strips 116).
The lay-up 110 may be cured and shaped to remove the sacrificial portion of the lay-up (the portion surrounding the line 118 in
As mentioned above, any of various cross-sectional profiles can be achieved by arranging strips of prepreg material in a predetermined manner. Examples of other face plate profiles that can be formed by the techniques described herein are disclosed in U.S. Pat. Nos. 6,800,038, 6,824,475, 6,904,663, and 7,066,832, all of which are incorporated herein by reference.
As mentioned above, the face plate 12 (
The metal cap 130 desirably is bonded to the composite plate 40 using a suitable adhesive 136, such as an epoxy, polyurethane, or film adhesive. The adhesive 136 is applied so as to fill the gap completely between the cap 130 and the composite plate 40 (this gap usually in the range of about 0.05-0.2 mm, and desirably is approximately 0.1 mm). The face plate 12 desirably is bonded to the body 14 using a suitable adhesive 138, such as an epoxy adhesive, which completely fills the gap between the rim 132 and the adjacent peripheral surface 140 of the face support 18 and the gap between the rear surface of the composite plate 40 and the adjacent peripheral surface 142 of the face support 18.
A particularly desirable metal for the cap 130 is titanium alloy, such as the particular alloy used for fabricating the body (e.g., Ti-6Al-4V). For a cap 130 made of titanium alloy, the thickness of the titanium desirably is less than about 1 mm, and more desirably less than about 0.3 mm. The candidate titanium alloys are not limited to Ti-6Al-4V, and the base metal of the alloy is not limited to Ti. Other materials or Ti alloys can be employed as desired. Examples include commercially pure (CP) grade Ti, aluminum and aluminum alloys, magnesium and magnesium alloys, and steel alloys.
Surface roughness can be imparted to the composite plate 40 (notably to any surface thereof that will be adhesively bonded to the body of the club-head and/or to the metal cap 130). In a first approach, a layer of textured film is placed on the composite plate 40 before curing the film (e.g., “top” and/or “bottom” layers discussed above). An example of such a textured film is ordinary nylon fabric. Conditions under which the adhesives 136, 138 are cured normally do not degrade nylon fabric, so the nylon fabric is easily used for imprinting the surface topography of the nylon fabric to the surface of the composite plate. By imparting such surface roughness, adhesion of urethane or epoxy adhesive, such as 3M® DP 460, to the surface of the composite plate so treated is improved compared to adhesion to a metallic surface, such as cast titanium alloy.
In a second approach, texture can be incorporated into the surface of the tool used for forming the composite plate 40, thereby allowing the textured area to be controlled precisely and automatically. For example, in an embodiment having a composite plate joined to a cast body, texture can be located on surfaces where shear and peel are dominant modes of failure.
The composite face plate as described above needs not be coextensive (dimensions, area, and shape) with a typical face plate on a conventional club-head. Alternatively, a subject composite face plate can be a portion of a full-sized face plate, such as the area of the “sweet spot.” Both such composite face plates are generally termed “face plates” herein. Further, the composite plate 40 itself (without additional layers of material bonded or formed on the composite plate) can be used as the face plate 12.
EXAMPLE 1In this example, a number of composite strike plates were formed using the strip approach described above in connection with
Table 1 also shows the average characteristic time (CT) (ball contact time with the strike plate) measured during the endurance test.
In this example, a number of composite strike plates were formed using the strip approach described above in connection with
The methods described above provide improved structural integrity of the face plates and other club-head components manufactured according to the methods, compared to composite component manufactured by prior-art methods. These methods can be used to fabricate face plates for any of various types of clubs, such as (but not limited to) irons, wedges, putter, fairway woods, etc., with little to no process-parameter changes.
The subject methods are especially advantageous for manufacturing face plates because face plates are the most severely loaded components in golf club-heads. If desired, conventional (and generally less expensive) composite-processing techniques (e.g., bladder-molding, etc.) can be used to make other parts of a club-head not subject to such severe loads.
Moreover, the methods for fabricating composite parts described herein can be used to make various other types of composite parts, and in particular, parts that are subject to high impact loads and/or repetitive loads. Some examples of such parts include, without limitation, a hockey stick (e.g., the blade of a stick), a bicycle frame, a baseball bat, and a tennis racket, to name a few.
EXAMPLE 3As shown in
The metallic cover 160 is generally made of a titanium alloy or other metal such as those mentioned above, and has a bulge/roll center 166 for bulge and roll curvatures that are provided to control club performance. Centers of curvature for bulge/roll curvatures are typically situated on an axis that is perpendicular to the striking surface 161 at the bulge/roll center 166. In this example, innermost edges of the scorelines 164a-164j are situated along a circumference of a circle having a diameter of about 40-50 mm that is centered at the bulge/roll center 166. As shown in the sectional view of
The striking region 162 can be roughened by sandblasting, bead blasting, sanding, or other abrasive process or by a machining or other process. The scorelines 164a-164j are situated outside of the intended striking region 162 and are generally provided for visual alignment and do not typically contribute to ball trajectory. A cross-section of a representative scoreline 164a is shown in
In other examples, a cover can be between about 0.10 mm and 1.0 mm thick, between about 0.2 mm and 0.8 mm thick, or between about 0.3 mm and 0.5 mm thick. Indentation depths between about 0.02 mm and 0.12 mm or about 0.06 mm and 0.10 mm are generally preferred for scoreline definition. Impact resistant cover plates with scorelines generally have scoreline depths D and cover plate thicknesses T such that a ratio D/T is less than about 0.4, 0.3, 0.25, or 0.20. A ratio WB/T is typically between about 0.5 and 1.5, 0.75 and 1.25, or 0.9 and 1.1. A ratio WG/T is typically between about 1 and 5, 2 and 4, or 2.5 and 3.5. A ratio of transition region radii of curvature R to cover thickness T is typically between about 0.5 and 1.5, 0.67 and 1.33, or 0.75 and 1.33. While it is convenient to provide scorelines based on common indentation depths, scorelines on a single cover can be based on indentations of one or more depths.
For wood-type golf clubs, an impact area is based on areas associated with inserts used in traditional wood golf clubs. For irons, an impact area is a portion of the striking surface within 20 mm on either side of a vertical centerline, but does not include 6.35 mm wide strips at the top and bottom of the striking surface. For wood-type golf clubs, scorelines are generally provided in a cover so as to be situated exterior to an impact region. The disclosed covers with scorelines are sufficiently robust for placement within or without an impact region for either wood or iron type golf clubs.
A cover is generally formed from a sheet of cover stock that is processed so as to have a bulge/roll region that includes the necessary arrangement of scoreline dents. The formed cover stock is then trimmed to fit an intended face plate, and attached to the face plate with an adhesive. Typically a glue layer is situated between the cover and the face plate, and the cover and face plate are urged together so as to form an adhesive layer of a suitable thickness. For typical adhesives, layer thicknesses between about 0.05 mm and 0.10 mm are preferred. Once a suitable layer thickness is achieved, the adhesive can be cured or allowed to set. In some cases, the cover includes a cover lip or rim as well so as to cover a face plate perimeter. The scoreline indentations are generally filled with paint of a color that contrasts with the remainder of the striking surface.
Although the scorelines are provided to realize a particular appearance in a finished product, the indentations used to define the scorelines also serve to control adhesive thickness. As a cover plate and a face plate are urged together in a gluing operation, the rear surface protrusions associated with the indentations tend to approach the face plate and thus regulate an adhesive layer thickness. Accordingly, indentation depth can be selected not only to retain paint or other pigment on a striking face, but can also be based on a preferred adhesive layer thickness. In some examples, protruding features of indentations in a cover plate are situated at distances of less than about 0.10 mm, 0.05 mm, 0.03 mm, and 0.01 mm from a face plate surface as an adhesive layer thickness is established.
In other examples, the indent-based scorelines shown in
In alternative embodiments, a cover includes a plurality of slots situated around a striking region. A suitably colored adhesive can be used to secure the cover layer to a face plate so that the adhesive fills the slots or is visible through the slots so to provide visible orientation guides on the striking plate surface.
EXAMPLE 4Polymer or other surface coatings or surface layers can be provided to composite or other face plates to provide performance similar to that of conventional irons and metal type woods. Such surface layers, methods of forming such layers, and characterization parameters for such layers are described below.
Surface Texture and RoughnessSurface textures or roughness can be conveniently characterized based on a surface profile, i.e., a surface height as a function of position on the surface. A surface profile is typically obtained by interrogating a sample surface with a stylus that is translated across the surface. Deviations of the stylus as a function of position are recorded to produce the surface profile. In other examples, a surface profile can be obtained based on other contact or non-contact measurements such as with optical measurements. Surface profiles obtained in this way are often referred to as “raw” profiles. Alternatively, surface profiles for a golf club striking surface can be functionally assessed based on shot characteristics produced when struck with surfaces under wet conditions.
For convenience, a control layer is defined as a striking face cover layer configured so that shots are consistent under wet and dry playing conditions. Generally, satisfactorily roughened or textured striking surfaces (or other control surfaces) provide ball spins that are similar to conventional metal faces under wet conditions when struck with club head speeds of between about 75 mph and 120 mph. Stylus or other measurement based surface roughness characterizations for such control surfaces are described in detail below.
A surface profile is generally processed to remove gradual deviations of the surface from flatness. For example, a wood-type golf club striking face generally has slight curvatures from toe-to-heel and crown-to-sole to improve ball trajectory, and a “raw” surface profile of a striking surface or a cover layer on the striking surface can be processed to remove contributions associated with these curvatures. Other slow (i.e., low spatial frequency) contributions can also be removed by such processing. Typically features of size of about 1 mm or greater (or spatial frequencies less than about 1/mm) can be removed by processing as the contributions of these features to wet ball spin about a horizontal or other axis tend to be relatively small. A raw (unprocessed) profile can be spatially filtered to enhance or suppress high or low spatial frequencies. Such filtering can be required in some measurements to conform to various standards such as DIN or other standards. This filtering can be performed using processors configured to execute a Fast Fourier Transform (FFT).
Generally, a patterned roughness or texture is applied to a substantial portion of a striking surface or at least to an impact area. For wood-type golf clubs, an impact area is based on areas associated with inserts used in traditional wood golf clubs. For irons, an impact area is a portion of the striking surface within 20 mm on either side of a vertical centerline, but does not include 6.35 mm wide strips at the top and bottom of the striking surface. Generally, such patterned roughness need not extend across the entire striking surface and can be provided only in a central region that does not extend to a striking surface perimeter. Typically for hollow metal woods, at least some portions of the striking surface at the striking surface perimeter lack pattern roughness in order to provide an area suitable for attachment of the striking plate to the head body.
Striking surface roughness can be characterized based on a variety of parameters. A surface profile is obtained over a sampling length of the striking surface and surface curvatures removed as noted above. An arithmetic mean Ra is defined a mean value of absolute values of profile deviations from a mean line over a sampling length of the surface. For a surface profile over the sampling length that includes N surface samples each of which is associated with a mean value of deviations Yi, from the mean line, the arithmetic mean Ra is:
wherein i is an integer i=1, . . . , N. The sampling length generally extends along a line on the striking surface over a substantial portion or all of the striking area, but smaller samples can be used, especially for a patterned roughness that has substantially constant properties over various sample lengths. Two-dimensional surface profiles can be similarly used, but one-dimensional profiles are generally satisfactory and convenient. For convenience, this arithmetic mean is referred to herein as a mean surface roughness.
A surface profile can also be further characterized based on a reciprocal of a mean width Sm of the profile elements. This parameter is used and described in one or more standards set forth by, for example, the German Institute for Standardization (DIN) or the International Standards Organization (ISO). In order to establish a value for Sm, an upper count level (an upward surface deviation associated with a peak) and a lower count level (a downward surface deviation associated with a valley) are defined. Typically, the upper count level and the lower count level are defined as values that are 5% greater than the mean line and 5% less than the mean line, but other count levels can be used. A portion of a surface profile projecting upward over the upper count level is called a profile peak, and a portion projecting downward below the given lower count level is called a profile valley. A width of a profile element is a length of the segment intersecting with a profile peak and the adjacent profile valley. Sm is a mean of profile element widths Smi within a sampling length:
For convenience, this mean is referred to herein as a mean surface feature width.
In determining Sm, the following conditions are generally satisfied: 1) Peaks and valleys appear alternately; 2) An intersection of the profile with the mean line immediately before a profile element is the start point of a current profile element and is the end point of a previous profile element; and 3) At the start point of the sampling length, if either of the profile peak or profile valley is missing, the profile element width is not taken into account. Rpc is defined as a reciprocal of the mean width Sm and is referred to herein as mean surface feature frequency.
Another surface profile characteristic is a surface profile kurtosis Ku that is associated with an extent to which profile samples are concentrated near the mean line. As used herein, the profile kurtosis Ku is defined as:
wherein Rq a square root of the arithmetic mean of the squares of the profile deviations from the mean line, i.e.,
Profile kurtosis is associated with an extent to which surface features are pointed or sharp. For example, a triangular wave shaped surface profile has a kurtosis of about 0.79, a sinusoidal surface profile has a kurtosis of about 1.5, and a square wave surface profile has a kurtosis of about 1.
Other parameters that can be used to characterize surface roughness include Rz which is based on a sum of a mean of a selected number of heights of the highest peaks and a mean of a corresponding number of depths of the lowest valleys.
One or more values or ranges of values can be specified for surface kurtosis Ku, mean surface feature width Sm, and arithmetic mean deviation Ra (mean surface roughness) for a particular golf club striking surface. Superior results are generally obtained with Ra≦5 μm, Rpc≧30/cm, and Ku≧2.0. However in certain embodiments, superior results are achieved with Ra being between about 4 μm and 5 μm or between about 4.5 μm and 5 μm. In addition, in similar embodiments, a superior Rpc is between about 20/cm and 30/cm or between about 22/cm and 28/cm. Finally, the Kt, is between about 1.5 and 2.5 or between about 1.7 and 2.2.
Wood-Type Club HeadsFor convenient illustration, representative examples of striking plates and cover layers for such striking plates are set forth below with reference to wood-type golf clubs. In other examples, such striking plates can be used in iron-type golf clubs. In some examples, face plate cover layers are formed on a surface of a face plate in a molding process, but in other examples surface layers are provided as caps that are formed and then secured to a face plate.
As illustrated in
Referencing
A club head origin coordinate system can also be used. Referencing
The head origin coordinate system, with head origin 260, includes three axes: a z-axis 265 extending through the head origin 260 in a generally vertical direction relative to the ground 100 when the club head 205 is at address position; an x-axis 270 extending through the head origin 60 in a heel-to-toe direction generally parallel to the striking face 240 and generally perpendicular to the z-axis 265; and a y-axis 275 extending through the head origin 260 in a front-to-back direction and generally perpendicular to the x-axis 270 and the z-axis 265. The x-axis 270 and the y-axis 275 both extend in a generally horizontal direction relative to the ground 299 when the club head 205 is at address position. The x-axis 270 extends in a positive direction from the origin 260 to the toe 250 of the club head 205; the y-axis 275 extends in a positive direction from the origin 260 towards the rear portion 255 of the club head 205; and the z-axis 265 extends in a positive direction from the origin 260 towards the crown 215.
In a club-head according to one embodiment, a striking plate includes a face plate and a cover layer. In addition, in some examples, at least a portion of the face plate is made of a composite including multiple plies or layers of a fibrous material (e.g., graphite, or carbon, fiber) embedded in a cured resin (e.g., epoxy). Examples of suitable polymers that can be used to form the cover layer include, without limitation, urethane, nylon, SURLYN ionomers, or other thermoset, thermoplastic, or other materials. The cover layer defines a striking surface that is generally a patterned, roughened, and/or textured surface as described in detail below. Striking plates based on composites typically permit a mass reduction of between about 5 g and 20 g in comparison with metal striking plates so that this mass can be redistributed.
In the example shown in
As shown in
Club face hardness or striking face hardness is generally measured based on a force required to produce a predetermined penetration of a probe of a standard size and/or shape in a selected time into a striking face of the club, or a penetration depth associated with a predetermined force applied to the probe. Based on such measurements, an effective Shore D hardness can be estimated. For the club faces described herein, the Shore D hardness scale is convenient, and effective Shore D hardnesses of between about 75 and 90 are generally obtained. In general, measured Shore D values decrease for longer probe exposures. Club face hardnesses as described herein are generally based on probe penetrations sufficient to produce an effective hardness estimate (an effective Shore D value) that can be associated with shot characteristics substantially similar to conventional wood or metal wood type golf clubs. The effective hardness generally depends on faceplate and polymer layer thicknesses and hardnesses.
As shown in
Cover layers such as the cover layer 330 can be formed and secured to a face plate using various methods. In one example, a striking surface of a cover layer is patterned with a mold. A selected roughness pattern is etched, machined, or otherwise transferred to a mold surface. The mold surface is then used to shape the striking surface of the cover layer for subsequent attachment to a composite face plate or other face plate. Such cover layers can be bonded with an adhesive to the face plate. Alternatively, the mold can be used to form the cover layer directly on the composite part. For example, a layer of a thermoplastic material (or pellets or other portions of such a material) can be situated on an external surface of a face plate, and the mold pressed against the thermoplastic material and the face plate at suitable temperatures and pressures so as to impress the roughness pattern on a thermoplastic layer, thereby forming a cover layer with a patterned surface. In another example, a thermoset material can be deposited on the external surface of the cover plate, and the mold pressed against the thermoset material and the face plate to provide a suitable cover layer thickness. The face plate, the thermoset material, and the mold are then raised to a suitable temperature so as to cure or otherwise fix the shape and thickness of the cover layer. These methods are examples only, and other methods can be used as may be convenient for various cover materials.
Representative Polymer MaterialsRepresentative polymer materials suitable for face plate covers or caps are described herein.
Definitions
The term “bimodal polymer” as used herein refers to a polymer comprising two main fractions and more specifically to the form of the polymer's molecular weight distribution curve, i.e., the appearance of the graph of the polymer weight fraction as a function of its molecular weight. When the molecular weight distribution curves from these fractions are superimposed onto the molecular weight distribution curve for the total resulting polymer product, that curve will show two maxima or at least be distinctly broadened in comparison with the curves for the individual fractions. Such a polymer product is called bimodal. The chemical compositions of the two fractions may be different.
The term “chain extender” as used herein is a compound added to either a polyurethane or polyurea prepolymer, (or the prepolymer starting materials), which undergoes additional reaction but at a level sufficiently low to maintain the thermoplastic properties of the final composition
The term “conjugated” as used herein refers to an organic compound containing two or more sites of unsaturation (e.g., carbon-carbon double bonds, carbon-carbon triple bonds, and sites of unsaturation comprising atoms other than carbon, such as nitrogen) separated by a single bond.
The term “curing agent” or “curing system” as used interchangeably herein is a compound added to either polyurethane or polyurea prepolymer, (or the prepolymer starting materials), which imparts additional crosslinking to the final composition to render it a thermoset.
The term “(meth)acrylate” is intended to mean an ester of methacrylic acid and/or acrylic acid.
The term “(meth)acrylic acid copolymers” is intended to mean copolymers of methacrylic acid and/or acrylic acid.
The term “polyurea” as used herein refers to materials prepared by reaction of a diisocyanate with a polyamine.
The term “polyurethane” as used herein refers to materials prepared by reaction of a diisocyanate with a polyol.
The term “prepolymer” as used herein refers to any material that can be further processed to form a final polymer material of a manufactured golf ball, such as, by way of example and not limitation, a polymerized or partially polymerized material that can undergo additional processing, such as crosslinking.
The term “thermoplastic” as used herein is defined as a material that is capable of softening or melting when heated and of hardening again when cooled.
Thermoplastic polymer chains often are not cross-linked or are lightly crosslinked using a chain extender, but the term “thermoplastic” as used herein may refer to materials that initially act as thermoplastics, such as during an initial extrusion process or injection molding process, but which also may be crosslinked, such as during a compression molding step to form a final structure.
The term “thermoplastic polyurea” as used herein refers to a material prepared by reaction of a prepared by reaction of a diisocyanate with a polyamine, with optionally addition of a chain extender.
The “thermoplastic polyurethane” as used herein refers to a material prepared by reaction of a diisocyanate with a polyol, with optionally addition of a chain extender.
The term “thermoset” as used herein is defined as a material that crosslinks or cures via interaction with as crosslinking or curing agent. The crosslinking may be brought about by energy in the form of heat (generally above 200° C.), through a chemical reaction (by reaction with a curing agent), or by irradiation. The resulting composition remains rigid when set, and does not soften with heating. Thermosets have this property because the long-chain polymer molecules cross-link with each other to give a rigid structure. A thermoset material cannot be melted and re-molded after it is cured thus thermosets do not lend themselves to recycling unlike thermoplastics, which can be melted and re-molded.
The term “thermoset polyurethane” as used herein refers to a material prepared by reaction of a diisocyanate with a polyol, and a curing agent.
The term “thermoset polyurea” as used herein refers to a material prepared by reaction of a diisocyanate with a polyamine, and a curing agent.
The term “urethane prepolymer” as used herein is the reaction product of diisocyante and a polyol.
The term “urea prepolymer” as used herein is the reaction product of a diisocyanate and a polyamine.
The term “unimodal polymer” refers to a polymer comprising one main fraction and more specifically to the form of the polymer's molecular weight distribution curve, i.e., the molecular weight distribution curve for the total polymer product shows only a single maximum.
Materials
Polymeric materials generally considered useful for making the golf club face cap according to the present invention include both synthetic or natural polymers or blend thereof including without limitation, synthetic and natural rubbers, thermoset polymers such as other thermoset polyurethanes or thermoset polyureas, as well as thermoplastic polymers including thermoplastic elastomers such as metallocene catalyzed polymer, unimodal ethylene/carboxylic acid copolymers, unimodal ethylene/carboxylic acid/carboxylate terpolymers, bimodal ethylene/carboxylic acid copolymers, bimodal ethylene/carboxylic acid/carboxylate terpolymers, unimodal ionomers, bimodal ionomers, modified unimodal ionomers, modified bimodal ionomers, thermoplastic polyurethanes, thermoplastic polyureas, polyamides, copolyamides, polyesters, copolyesters, polycarbonates, polyolefins, halogenated (e.g. chlorinated) polyolefins, halogenated polyalkylene compounds, such as halogenated polyethylene [e.g. chlorinated polyethylene (CPE)], polyalkenamer, polyphenylene oxides, polyphenylene sulfides, diallyl phthalate polymers, polyimides, polyvinyl chlorides, polyamide-ionomers, polyurethane-ionomers, polyvinyl alcohols, polyarylates, polyacrylates, polyphenylene ethers, impact-modified polyphenylene ethers, polystyrenes, high impact polystyrenes, acrylonitrile-butadiene-styrene copolymers, styrene-acrylonitriles (SAN), acrylonitrile-styrene-acrylonitriles, styrene-maleic anhydride (S/MA) polymers, styrenic copolymers, functionalized styrenic copolymers, functionalized styrenic terpolymers, styrenic terpolymers, cellulosic polymers, liquid crystal polymers (LCP), ethylene-propylene-diene terpolymers (EPDM), ethylene-vinyl acetate copolymers (EVA), ethylene-propylene copolymers, ethylene vinyl acetates, polyureas, and polysiloxanes and any and all combinations thereof.
One preferred family of polymers for making the golf club face cap of the present invention are the thermoplastic or thermoset polyurethanes and polyureas made by combination of a polyisiocyanate and a polyol or polyamine respectively. Any isocyanate available to one of ordinary skill in the art is suitable for use in the present invention including, but not limited to, aliphatic, cycloaliphatic, aromatic aliphatic, aromatic, any derivatives thereof, and combinations of these compounds having two or more isocyanate (NCO) groups per molecule.
Any polyol available to one of ordinary skill in the polyurethane art is suitable for use according to the invention. Polyols suitable for use include, but are not limited to, polyester polyols, polyether polyols, polycarbonate polyols and polydiene polyols such as polybutadiene polyols.
Any polyamine available to one of ordinary skill in the polyurea art is suitable for use according to the invention. Polyamines suitable for use include, but are not limited to, amine-terminated hydrocarbons, amine-terminated polyethers, amine-terminated polyesters, amine-terminated polycaprolactones, amine-terminated polycarbonates, amine-terminated polyamides, and mixtures thereof.
The previously described diisocyante and polyol or polyamine components may be previously combined to form a prepolymer prior to reaction with the chain extender or curing agent. Any such prepolymer combination is suitable for use in the present invention. Commercially available prepolymers include LFH580, LFH120, LFH710, LFH1570, LF930A, LF950A, LF601D, LF751D, LFG963A, LFG640D.
One preferred prepolymer is a toluene diisocyanate prepolymer with polypropylene glycol. Such polypropylene glycol terminated toluene diisocyanate prepolymers are available from Uniroyal Chemical Company of Middlebury, Conn., under the trade name ADIPRENE® LFG963A and LFG640D. Most preferred prepolymers are the polytetramethylene ether glycol terminated toluene diisocyanate prepolymers including those available from Uniroyal Chemical Company of Middlebury, Conn., under the trade name ADIPRENE® LF930A, LF950A, LF601D, and LF751D.
Polyol chain extenders or curing agents may be primary, secondary, or tertiary polyols. Diamines and other suitable polyamines may be added to the compositions of the present invention to function as chain extenders or curing agents. These include primary, secondary and tertiary amines having two or more amines as functional groups.
Depending on their chemical structure, curing agents may be slow- or fast-reacting polyamines or polyols. As described in U.S. Pat. Nos. 6,793,864, 6,719,646 and copending U.S. Patent Publication No. 2004/0201133 A1, (the contents of all of which are hereby incorporated herein by reference).
Suitable curatives for use in the present invention are selected from the slow-reacting polyamine group include, but are not limited to, 3,5-dimethylthio-2,4-toluenediamine; 3,5-dimethylthio-2,6-toluenediamine; N,N′-dialkyldiamino diphenyl methane; trimethylene-glycol-di-p-aminobenzoate; polytetramethyleneoxide-di-p-aminobenzoate, and mixtures thereof. Of these, 3,5-dimethylthio-2,4-toluenediamine and 3,5-dimethylthio-2,6-toluenediamine are isomers and are sold under the trade name ETHACURE® 300 by Ethyl Corporation. Trimethylene glycol-di-p-aminobenzoate is sold under the trade name POLACURE 740M and polytetramethyleneoxide-di-p-aminobenzoates are sold under the trade name POLAMINES by Polaroid Corporation. N,N′-dialkyldiamino diphenyl methane is sold under the trade name UNILINK® by UOP. Suitable fast-reacting curing agent can be used include diethyl-2,4-toluenediamine, 4,4″-methylenebis-(3-chloro,2,6-diethyl)-aniline (available from Air Products and Chemicals Inc., of Allentown, Pa., under the trade name LONZACURE®), 3,3′-dichlorobenzidene; 3,3′-dichloro-4,4′-diaminodiphenyl methane (MOCA); N,N,N′,N′-tetrakis(2-hydroxypropyl)ethylenediamine and Curalon L, a trade name for a mixture of aromatic diamines sold by Uniroyal, Inc. or any and all combinations thereof A preferred fast-reacting curing agent is diethyl-2,4-toluene diamine, which has two commercial grades names, Ethacure® 100 and Ethacure 100LC commercial grade has lower color and less by-product. Blends of fast and slow curing agents are especially preferred.
In another preferred embodiment the polyurethane or polyurea is prepared by combining a diisocyanate with either a polyamine or polyol or a mixture thereof and one or more dicyandiamides. In a preferred embodiment the dicyandiamide is combined with a urethane or urea prepolymer to form a reduced-yellowing polymer composition as described in U.S. Patent Application No. 60/852,582 filed on Oct. 17, 2006, the entire contents of which are herein incorporated by reference in their entirety. Another preferred family of polymers for making the golf club face cap of the present invention are thermoplastic ionomer resins. One family of such resins was developed in the mid-1960's, by E.I. DuPont de Nemours and Co., and sold under the trademark SURLYN®. Preparation of such ionomers is well known, for example see U.S. Pat. No. 3,264,272. Generally speaking, most commercial ionomers are unimodal and consist of a polymer of a mono-olefin, e.g., an alkene, with an unsaturated mono- or dicarboxylic acids having 3 to 12 carbon atoms. An additional monomer in the form of a mono- or dicarboxylic acid ester may also be incorporated in the formulation as a so-called “softening comonomer”. The incorporated carboxylic acid groups are then neutralized by a basic metal ion salt, to form the ionomer. The metal cations of the basic metal ion salt used for neutralization include Li+, Na+, K+, Zn2+, Ca2+, Co2+, Ni2+, Cu2+, Pb2+, and Mg2+, with the Li+, Na+, Ca2+, Zn2+, and Mg2+ being preferred. The basic metal ion salts include those derived by neutralization of for example formic acid, acetic acid, nitric acid, and carbonic acid. The salts may also include hydrogen carbonate salts, metal oxides, metal hydroxides, and metal alkoxides.
Today, there are a wide variety of commercially available ionomer resins based both on copolymers of ethylene and (meth)acrylic acid or terpolymers of ethylene and (meth)acrylic acid and (meth)acrylate, all of which many of which are be used as a golf club component such as a cover layer that provides a striking surface. The properties of these ionomer resins can vary widely due to variations in acid content, softening comonomer content, the degree of neutralization, and the type of metal ion used in the neutralization. The full range commercially available typically includes ionomers of polymers of general formula, E/X/Y polymer, wherein E is ethylene, X is a C3 to C8 α,β ethylenically unsaturated carboxylic acid, such as acrylic or methacrylic acid, and is present in an amount from about 2 to about 30 weight % of the E/X/Y copolymer, and Y is a softening comonomer selected from the group consisting of alkyl acrylate and alkyl methacrylate, such as methyl acrylate or methyl methacrylate, and wherein the alkyl groups have from 1-8 carbon atoms, Y is in the range of 0 to about 50 weight % of the E/X/Y copolymer, and wherein the acid groups present in said monomeric polymer are partially neutralized with a metal selected from the group consisting of lithium, sodium, potassium, magnesium, calcium, barium, lead, tin, zinc or aluminum, and combinations thereof.
The ionomer may also be a so-called bimodal ionomer as described in U.S. Pat. No. 6,562,906 (the entire contents of which are herein incorporated by reference). These ionomers are bimodal as they are prepared from blends comprising polymers of different molecular weights In addition to the unimodal and bimodal ionomers, also included are the so-called “modified ionomers” examples of which are described in U.S. Pat. Nos. 6,100,321, 6,329,458 and 6,616,552 and U.S. Patent Publication U.S. 2003/0158312 A1, the entire contents of all of which are herein incorporated by reference. An example of such a modified ionomer polymer is DuPont® HPF-1000 available from E.I. DuPont de Nemours and Co. Inc.
Also useful for making the golf club face cap of the present invention is a blend of an ionomer and a block copolymer. A preferred block copolymer is SEPTON HG-252. Such blends are described in more detail in commonly-assigned U.S. Pat. No. 6,861,474 and U.S. Patent Publication No. 2003/0224871 both of which are incorporated herein by reference in their entireties.
In a further embodiment, the golf club face cap of the present invention can comprise a composition prepared by blending together at least three materials, identified as Components A, B, and C, and melt-processing these components to form in-situ, a polymer blend composition incorporating a pseudo-crosslinked polymer network. Such blends are described in more detail in commonly-assigned U.S. Pat. No. 6,930,150, to Kim et al., the content of which is incorporated by reference herein in its entirety.
Component A is a monomer, oligomer, prepolymer or polymer that incorporates at least five percent by weight of at least one type of an acidic functional group. Examples of such polymers suitable for use as include, but are not limited to, ethylene/(meth)acrylic acid copolymers and ethylene/(meth)acrylic acid/alkyl (meth)acrylate terpolymers, or ethylene and/or propylene maleic anhydride copolymers and terpolymers.
As discussed above, Component B can be any monomer, oligomer, or polymer, preferably having a lower weight percentage of anionic functional groups than that present in Component A in the weight ranges discussed above, and most preferably free of such functional groups. Preferred materials for use as Component B include polyester elastomers marketed under the name PEBAX and LOTADER marketed by ATOFINA Chemicals of Philadelphia, Pa.; HYTREL, FUSABOND, and NUCREL marketed by E.I. DuPont de Nemours & Co. of Wilmington, Del.; SKYPEL and SKYTHANE by S.K. Chemicals of Seoul, South Korea; SEPTON and HYBRAR marketed by Kuraray Company of Kurashiki, Japan; ESTHANE by Noveon; and KRATON marketed by Kraton Polymers. A most preferred material for use as Component B is SEPTON HG-252. Component C is a base capable of neutralizing the acidic functional group of Component A and is a base having a metal cation. These metals are from groups IA, IB, IIA, IIB, IIIA, IIIB, IVA, IVB, VA, VB, VIA, VIB, VIIB and VIIIB of the periodic table. Examples of these metals include lithium, sodium, magnesium, aluminum, potassium, calcium, manganese, tungsten, titanium, iron, cobalt, nickel, hafnium, copper, zinc, barium, zirconium, and tin. Suitable metal compounds for use as a source of Component C are, for example, metal salts, preferably metal hydroxides, metal oxides, metal carbonates, or metal acetates. The composition preferably is prepared by mixing the above materials into each other thoroughly, either by using a dispersive mixing mechanism, a distributive mixing mechanism, or a combination of these.
In a further embodiment, the golf club face cap of the present invention can comprise a polyamide. Specific examples of suitable polyamides include polyamide 6; polyamide 11; polyamide 12; polyamide 4,6; polyamide 6,6; polyamide 6,9; polyamide 6,10; polyamide 6,12; polyamide MXD6; PA12,CX; PA12, IT; PPA; PA6, IT; and PA6/PPE.
The polyamide may be any homopolyamide or copolyamide. One example of a group of suitable polyamides is thermoplastic polyamide elastomers. Thermoplastic polyamide elastomers typically are copolymers of a polyamide and polyester or polyether. For example, the thermoplastic polyamide elastomer can contain a polyamide (Nylon 6, Nylon 66, Nylon 11, Nylon 12 and the like) as a hard segment and a polyether or polyester as a soft segment. In one specific example, the thermoplastic polyamides are amorphous copolyamides based on polyamide (PA 12). Suitable amide block polyethers include those as disclosed in U.S. Pat. Nos. 4,331,786; 4,115,475; 4,195,015; 4,839,441; 4,864,014; 4,230,848 and 4,332,920.
One type of polyetherester elastomer is the family of Pebax, which are available from Elf-Atochem Company. Preferably, the choice can be made from among Pebax 2533, 3533, 4033, 1205, 7033 and 7233. Blends or combinations of Pebax 2533, 3533, 4033, 1205, 7033 and 7233 can also be prepared, as well. Some examples of suitable polyamides for use include those commercially available under the trade names PEBAX, CRISTAMID and RILSAN marketed by Atofina Chemicals of Philadelphia, Pa., GRIVORY and GRILAMID marketed by EMS Chemie of Sumter, South Carolina, TROGAMID and VESTAMID available from Degussa, and ZYTEL marketed by E.I. DuPont de Nemours & Co., of Wilmington, Del.
The polymeric compositions used to prepare the golf club face cap of the present invention also can incorporate one or more fillers. Such fillers are typically in a finely divided form, for example, in a size generally less than about 20 mesh, preferably less than about 100 mesh U.S. standard size, except for fibers and flock, which are generally elongated. Filler particle size will depend upon desired effect, cost, ease of addition, and dusting considerations. The appropriate amounts of filler required will vary depending on the application but typically can be readily determined without undue experimentation.
The filler preferably is selected from the group consisting of precipitated hydrated silica, limestone, clay, talc, asbestos, barytes, glass fibers, aramid fibers, mica, calcium metasilicate, barium sulfate, zinc sulfide, lithopone, silicates, silicon carbide, diatomaceous earth, carbonates such as calcium or magnesium or barium carbonate, sulfates such as calcium or magnesium or barium sulfate, metals, including tungsten, steel, copper, cobalt or iron, metal alloys, tungsten carbide, metal oxides, metal stearates, and other particulate carbonaceous materials, and any and all combinations thereof. Preferred examples of fillers include metal oxides, such as zinc oxide and magnesium oxide. In another preferred embodiment the filler comprises a continuous or non-continuous fiber. In another preferred embodiment the filler comprises one or more so called nanofillers, as described in U.S. Pat. No. 6,794,447 and copending U.S. patent application Ser. No. 10/670,090 filed on Sep. 24, 2003 and copending U.S. patent application Ser. No. 10/926,509 filed on Aug. 25, 2004, the entire contents of each of which are incorporated herein by reference.
Another particularly well-suited additive for use in the compositions of the present invention includes compounds having the general formula:
(R2N)m—R′—(X(O)nORy)m,
wherein R is hydrogen, or a C1-C20 aliphatic, cycloaliphatic or aromatic systems; R′ is a bridging group comprising one or more C1-C20 straight chain or branched aliphatic or alicyclic groups, or substituted straight chain or branched aliphatic or alicyclic groups, or aromatic group, or an oligomer of up to 12 repeating units including, but not limited to, polypeptides derived from an amino acid sequence of up to 12 amino acids; and X is C or S or P with the proviso that when X═C, n=1 and y=1 and when X═S, n=2 and y=1, and when X═P, n=2 and y=2. Also, m=1-3. These materials are more fully described in copending U.S. patent application Ser. No. 11/182,170, filed on Jul. 14, 2005, the entire contents of which are incorporated herein by reference. Most preferably the material is selected from the group consisting of 4,4′-methylene-bis-(cyclohexylamine)-carbamate (commercially available from R.T. Vanderbilt Co., Norwalk Conn. under the trade name Diak® 4), 11-aminoundecanoicacid, 12-aminododecanoic acid, epsilon-caprolactam; omega-caprolactam, and any and all combinations thereof.
If desired, the various polymer compositions used to prepare the golf club face cap of the present invention can additionally contain other conventional additives such as, antioxidants, or any other additives generally employed in plastics formulation. Agents provided to achieve specific functions, such as additives and stabilizers, can be present. Exemplary suitable ingredients include plasticizers, pigments colorants, antioxidants, colorants, dispersants, U.V. absorbers, optical brighteners, mold releasing agents, processing aids, fillers, and any and all combinations thereof. UV stabilizers, or photo stabilizers such as substituted hydroxphenyl benzotriazoles may be utilized in the present invention to enhance the UV stability of the final compositions. An example of a commercially available UV stabilizer is the stabilizer sold by Ciba Geigy Corporation under the trade name TINUVIN.
Representative “Peel Ply” MethodIn another method, a layer of a so-called “peel ply” fabric is bonded to an exterior surface of a composite face plate (preferably as the face plate is fabricated) or to a striking surface on a polymer cover layer. In some examples, a thermoset material is used for the cover layer, while in other examples thermoplastic materials are used. With either type of material, the peel ply fabric is removably bonded to the cover layer (or to the face plate). The peel ply fabric is removed from the cover layer, leaving a textured or roughened striking surface. A striking surface texture can be selected based upon peel ply fabric texture, fabric orientation, and fiber size so as to achieve surface characteristics comparable to conventional metal woods and irons.
A representative peel ply based process is illustrated in
Representative surface profiles of peel ply based striking surfaces are shown in
An example striking plate 810 based on a machined or other mold is shown in
The following Table 3 summarizes surface roughness parameters associated with the scans of
A striking surface of a cover layer can be provided with a variety of other roughness patterns some examples of which are illustrated in
While the pattern features 412 may have substantially constant cross-sectional dimensions in one or more planes perpendicular the xz-plane (i.e. vertical cross-sections), these vertical cross-sections can vary along a y-axis 424 or as a function of an angle of a cross-sectional plane with respect to the x-axis, the y-axis, or the z-axis. For example, columnar protrusions can have bases that taper outwardly, inwardly, or a combination thereof along the y-axis 424, and can be tilted with respect to the y-axis 424.
In an example shown in
In other examples, pattern features can be periodic, aperiodic, or partially periodic, or randomly situated. Spatial frequencies associated with pattern features can vary, and pattern feature size and orientation can vary as well. In some examples, a roughened surface is defined as series of features that are randomly situated and sized.
Similar striking plates can be provided for iron-type golf clubs. While striking plates for wood-type golf clubs generally have top-to-bottom and toe-to-heel curvatures (commonly referred to as bulge and roll), striking plates for irons are typically flat. Composite-based striking plates for iron-type clubs typically include a polymer cover layer selected to protect the underlying composite face plate. In some examples, similar striking surface textures to those described above can be provided. In addition, one or more conventional grooves are generally provided on the striking surface. Such striking plates can be secured to iron-type golf club bodies with various adhesives or otherwise secured.
Roughness-Efficient SurfacesCertain features of a golf club face surface are significant in terms of striking a golf ball. Surface features that are included in the Ra calculation, but do not aid in striking the ball, can be removed or minimized without compromising the performance of the golf club face. Removing or minimizing such features can enable the addition of more performance-effective features for a given Ra.
One approach for achieving a “roughness-efficient” surface profile is to make non-critical transition segments that are between critical ball-striking segments (e.g., a peak or a valley) occur as closely to the mean line of the profile as possible. The most efficient approach is to have the transition segment fall directly on, or near to, the mean line. Thus, in one embodiment, a substantial portion of the transition segment is near to, or on, the mean line. For example, at least 50%, particularly at least 75%, more particularly at least 90%, and most particularly 100%, of the transition segment is near to, or on, the mean line. In certain embodiments, at least 50%, particularly at least 75%, more particularly at least 90%, and most particularly 100%, of the transition segment is on the mean line. In one embodiment, the phrase “on the mean line” can be defined as the portion of a segment that is within about 10% of the mathematically calculated mean line, defined herein.
A further efficient approach is to make the transitions between the mean line and the critical peaks and valleys occur as quickly as possible (i.e., transition segments with steep slopes). For instance, the transition segment may include a portion having a slope of at least 30°, more particularly at least 45°, and most particularly, at least 75°, relative to the mean line. The sloped portion may constitute at least 25%, particularly at least 50%, more particularly at least 75%, and most particularly 100%, of the transition segment. In particular embodiments, the transition segment may include a first portion that is a straight line that lies on the mean line, and a second portion that is a line having a slope relative to the mean line as described above.
As used herein, a “peak” refers to a segment of a surface profile that includes a point or line located at a maxima (either locally or globally) above the mean line. For instance, the peak may be in the shape of a curve with an inflection point at a maxima above the mean line as shown in
A “valley” refers to a segment of a surface profile that includes a point or line located at a maxima (either locally or globally) below the mean line. For instance, the valley may be in the shape of a curve with an inflection point at a maxima below the mean line as shown in
The segment of the surface profile between a peak and an adjacent valley is referred to herein as a “transition segment”. Illustrative transition segment shapes include lines parallel to, or directly on, the mean line, straight lines sloped at an angle relative to the mean line, or curved lines. Examples of a transition segment are identified in
The “mean line” or “center line” is the line that divides a sampling length of surface (L) so that the sum of areas above this line is equal to the sum of areas below the line. The mean line 1000 is shown in
Area (A+C+E+G+I)=Area (B+D+F+H+J+K), as shown in
An overall goal of more roughness-efficient surface profiles is to maximize Ry for a desired or predetermined Ra. Ry is the area that falls under the highest peak of a surface profile and this is the area that the ball impacts. In some cases, it is also desirable to maximize Rpc.
Examples of roughness-efficient surface profiles 1001 for striking surface roughness patterns are shown in
A striking surface of a golf club head can be provided with a variety of roughness-efficient patterns as described herein or with a single roughness-efficient pattern as described herein. Typically these patterns extend over substantially the entire striking surface, but in some examples only a portion of the striking surface is patterned.
A striking plate includes a composite face plate and a cover layer. A striking surface of the cover layer includes a patterned area that includes a plurality of pattern features that are arranged in a two dimensional array. The pattern features are surface profiles as described herein wherein the valleys are formed in the cover layer and extend along a +y-direction (i.e., inwardly towards an external surface of the face plate). A horizontal spacing (along an x-axis) of the pattern features is dx and a vertical spacing (along a z-axis) is dz. These spacings can be the same or different, and the features can be inwardly or outwardly directed. In addition, for cross-sectional shapes that are asymmetric, the pattern features can be arbitrarily aligned with respect to the x-axis and the z-axis. The pattern features can be located in a regular array, but the orientation of each of the pattern features can be arbitrary, or the pattern features can be periodically arranged along the x-axis, the z-axis, or another axis in the xz-plane. A plurality of scorelines may be provided in addition to the roughness-efficient pattern and are typically colored so as to provide a high contrast. A maximum depth dy of the pattern features along the y-axis is between about 10 μm and 100 μm, between about 5 μm and 50 μm, or about 2 μm and 25 μm. The horizontal and vertical spacings are typically between about 0.025 mm and 0.500 mm
While the pattern features may have substantially constant cross-sectional dimensions in one or more planes perpendicular the xz-plane (i.e. vertical cross-sections), these vertical cross-sections can vary along a y-axis or as a function of an angle of a cross-sectional plane with respect to the x-axis, the y-axis, or the z-axis. For example, columnar protrusions can have bases that taper outwardly, inwardly, or a combination thereof along the y-axis, and can be tilted with respect to the y-axis.
Similar striking plates can be provided for iron-type golf clubs. While striking plates for wood-type golf clubs generally have top-to-bottom and toe-to-heel curvatures (commonly referred to as roll and bulge), striking plates for irons are typically flat. Composite-based striking plates for iron-type clubs typically include a polymer cover layer selected to protect the underlying composite face plate. In some examples, similar striking surface textures to those described above can be provided. In addition, one or more conventional grooves are generally provided on the striking surface. Such striking plates can be secured to iron-type golf club bodies with various adhesives or otherwise secured.
Machining the roughened surface profiles into a mold that is then used to cast a cover for a golf club face can be an effective manufacturing method for a controllable and repeatable technique for prescribing wherein the mean line falls on the profile plot. In certain embodiments, the cover that includes the roughness-efficient surface profiles described herein is made from a non-metallic material such as a polymeric material as described above. In other embodiments, the striking surface with the roughness-efficient pattern is made from a metallic material such as titanium or a metal/polymer composite as described above.
The roughness-efficient surface profiles described herein can be utilized with any type of golf club.
Asymmetric Surface TexturesSimilarly to the roughness efficient texture, an asymmetric surface texture may provide more efficient roughness performance compared to a symmetric texture. Several exemplary impact surface texture geometries are shown in
Exemplary impact surface textures can be relatively smooth in a horizontal, heel-toe direction and can be contoured in a vertical, sole-crown direction. Preferably, the surface texture can be asymmetric in the sole-crown direction. An exemplary metal-wood type golf club head 902 is shown in
As shown in
The geometry of a ridge 910 can be characterized in terms of the slopes of the upwardly facing surface 916 and the downwardly facing surface 918 of the ridge. The slope S1 of an upwardly facing surface 916 can be defined as the ratio H/X1 and the slope S2 of a downwardly facing surface 918 can be defined as the ratio H/X2.
When X1 and X2 are equal (S1 and S2 are equal), the surface texture is symmetric in the sole-crown direction.
When X1 and X2 are not equal, the surface texture is asymmetric in the sole-crown direction. When X2 is greater than X1 (S1 is greater than S2), the peaks 912 slant upwardly and the texture can be referred to as “asymmetric-up.”
When X1 is greater than X2 (S1 is less than S2), the peaks 912 slant downwardly and the surface texture can be referred to as “asymmetric-down.”
A surface texture that is asymmetric in the sole-crown direction can be symmetric and/or constant in the perpendicular heel-toe direction. In other words, the values of H, P, X1 and X2 can be constant moving across the face 906 in the heel-toe direction, with parallel peaks 912 and valleys 914 and ridges 910 that have a cross-sectional profile that is constant in the heel-toe direction. Referring again to
In some embodiments, the surface texture of the impact surface of the golf club can be varied across the impact surface. For example, the surface texture can vary in the sole-crown direction such that the ratio X1/X2 is highest nearer to the crown and becomes gradually lower at locations moving downward toward the sole. The surface texture can vary in the heel-toe direction as well.
The surface texture of the impact surface can affect the launch angle of the ball. In particular, asymmetric-up surface textures can result in an increased launch angle compared to a smooth impact surface, which can result in increased shot distance.
A surface texture can be applied to all or only a portion of the impact surface of the face. For example, the surface texture need not extend across the entire impact surface and can be provided only in a central region of the impact surface that does not extend to a perimeter of the face. For hollow metal-woods, at least some portions of the impact surface at the perimeter of the face can lack surface texture in order to provide an area suitable for attachment of the face to the head body.
An exemplary golf club embodiment that includes a face comprising a composite plate with a polymer cover on the impact surface as described in U.S. Pat. No. 7,874,936, which is incorporated herein by reference. This golf club can further comprise an asymmetric-up surface texture on the impact surface, such as those shown in
Polymeric cover layers on the impact surface of the face can be formed and secured to a face plate using various methods. In some embodiments, a texture can be formed on the outer impact surface of a cover layer with a mold. For example, a selected surface texture can be etched, machined, or otherwise transferred to the mold surface. The mold can be used to form a cover layer having a textured impact surface, which can then be attached to a composite face plate or face plate comprised of other materials. Such cover layers can be bonded with an adhesive to the face plate.
Alternatively, a mold can be used to form the cover layer directly on the composite face plate. For example, a layer of a thermoplastic material (or pellets or other portions of such a material) can be placed on an external surface of a pre-formed face plate, and the assembly can be placed in a mold. The mold has a surface with the desired surface texture adjacent the polymeric material. The mold surfaces can be pressed against the thermoplastic material and the face plate at suitable temperatures and pressures so as to impress the desired surface texture on a thermoplastic layer, thereby forming a cover layer with a desired surface texture. In another example, a thermoset material can be deposited on the external surface of the face plate, and the mold pressed against the thermoset material and the face plate to form a cover layer having a desired thickness and texture. The face plate, the thermoset material, and the mold can then be raised to a suitable temperature so as to cure or otherwise fix the shape and thickness of the cover layer. Exemplary materials are described above.
In other embodiments, a composite face plate and textured layer can be formed at the same time in a mold. For example, a lay-up can be formed from a plurality of pre-preg composite sheets (as disclosed in U.S. Pat. No. 7,874,936) and a layer of polymeric material to form the cover layer of the face plate. The lay-up can be placed in a mold, which applies heat and/or pressure to the lay-up to form a molded part. The cured, molded part can then be removed from the mold and machined as needed to achieve the final shape and size of the face plate. These methods are examples only, and other methods can be used as may be convenient for forming cover layers for face plates.
In other embodiments, the desired surface texture can be machined or otherwise formed directly on the face plate. For example, a desired surface texture can be machined directly into a metal (e.g., titanium) face plate.
ScorelinesAs described above and as shown in several of the figures, a plurality of scorelines may be provided on the striking surface of the striking plate. In some embodiments, the striking plate includes a composite face plate and a polymer cover. In those embodiments, the scorelines extend inwardly into the surface of the cover layer from the exterior most surface of the cover layer. The scorelines may be provided in addition to the surface texture features described herein, or without a surface texture. Several exemplary scoreline profiles and scoreline dimensions are shown in and described by reference to
An exemplary metal-wood type golf club head 1002 is shown in
An exemplary striking plate 1006 for the metal-wood type golf club head 1002 is shown in
The embodiment of the striking plate 1006 shown in
As noted above, the center zone 1040 may be described by reference to
The impact zone 1050 may be described by reference to
Finally, the peripheral zone 1060 may also be described by reference to
A plurality of scorelines 1030 is formed on the impact surface 1008 of the striking plate 1006 as shown, for example, in
An exemplary scoreline profile is shown in
The scoreline depth Dsl is typically measured in an orientation normal to the impact surface 1008 of the striking plate 1006 from the deepest portion of the scoreline 1030 to a plane representative of the impact surface 1008 at a land area 1032 adjacent to the scoreline. In some embodiments, the scoreline depth Dsl is between 0.1 mm and 0.508 mm, such as between 0.15 mm and 0.4 mm, such as between 0.15 mm and 0.35 mm.
The scoreline width Wsl is measured according to the USGA 30 degree measurement method, in which an edge of the scoreline is designated to be the point on the edge radius where a line inclined at 30 degrees to the land area 1032 of the club face is tangent, and the scoreline width Wsl is measured from edge to edge, as shown for example in
The scoreline 1030 may also be described by reference to its edge radii, Re, and bottom radii, Rb. In the embodiment shown in
The areas between adjacent scorelines 1030 are designated as land areas 1032. In the example shown in
As noted above, the center zone 1040 is an area on the impact surface 1008 that is free of scorelines. (See, e.g.,
In several embodiments, the impact zone 1050 is provided with scorelines 1030 having scoreline widths, Wsl, scoreline lengths, Lsl, land area widths, Wla, and scoreline separations, Ssl, that provide at least a minimum value for a ratio of scoreline area to impact zone area. In particular, the area of a scoreline, Asl, is generally defined herein as the product of the scoreline width, Wsl, and its length, Lsl. In other words, Asl=Wsl×Lsl. The scoreline area, Asl, may be calculated for the full length of a given scoreline, or for a designated portion of the length of a scoreline, such as the length of a scoreline within the impact zone 1050. It is also contemplated that if the scoreline width, Wsl, varies over the relevant portion of its length, then these variations may be accounted for in the calculation by determining an effective width, Wsl', over the relevant length, Lsl, in order to determine the appropriate measured area, Asl.
The scoreline area, Asl, is the sum of the areas of the scorelines 1030 for a given are of the impact surface 1008. Accordingly, the scoreline area of the impact zone 1050, Asliz, is the sum of the areas of those portions of the scorelines provided within the impact zone 1050. Table 4 below summarizes the scoreline dimensions of several scoreline profile embodiments described herein. For each embodiment, Table 4 also lists the calculated scoreline area within the impact zone 1050, Asliz, the impact zone area, Aiz, and the impact zone scoreline area ratio Asliz/Aiz.
In the examples listed in Table 4, each of the scorelines 1030 in the impact zone 1050 extends across the full length of the impact zone 1050 with the exception of a single scoreline having a 4 mm discontinuity at the center zone 1040.
The results presented in Table 4 show that the scoreline profiles of several of the embodiments described herein included a value for the scoreline area within the impact zone 1050, Asliz, of at least 130 mm2, such as at least 200 mm2, such as at least 300 mm2. These scoreline profile embodiments also provided a ratio of scoreline area within the impact zone 1050, Asliz, to the area of the impact zone, Aiz, of at least 0.10, such as at least 0.17, such as at least 0.20. Moreover, the described scoreline profile embodiments provide ranges of the ratio Asliz/Aiz that are between about 0.10 to about 0.30, such as between about 0.10 to about 0.25, such as between about 0.17 to about 0.30, or such as between about 0.17 to about 0.25. These values for scoreline area, Asliz, and the ratio of scoreline area to impact zone area, Asliz/Aiz, can enable the composite face plate of the club heads described herein to perform substantially the same as a standard all-metal face plates under wet conditions.
Several of the club head embodiments described herein also include scoreline profiles in the peripheral zone 1060 that provide a ratio of scoreline area, Aslpz, within the peripheral zone 1060 to the area of the peripheral zone, Apz, that are the same as the comparable ratio in the impact zone 1050. For example, in these embodiments, the ratio Aslpz/Apz for the peripheral zone 1060 is at least 0.10, such as at least 0.17, such as at least 0.20. Moreover, the described scoreline profile embodiments provide ranges of the ratio Aslpz/Apz that are between about 0.10 to about 0.30, such as between about 0.10 to about 0.25, such as between about 0.17 to about 0.30, or such as between about 0.17 to about 0.25. In several of these embodiments, such as those shown in
The scoreline profiles described herein can be provided on all or only a portion of the impact surface of the face. For example, for hollow metal-woods, at least some portions of the impact surface at the perimeter of the face can lack scorelines in order to provide an area suitable for attachment of the face to the head body.
An exemplary golf club embodiment that includes a face comprising a composite plate with a polymer cover on the impact surface as described in U.S. Pat. No. 7,874,936, which is incorporated herein by reference. This golf club can further comprise a scoreline profile on the impact surface, such as those shown in
Polymeric cover layers on the impact surface of the face can be formed and secured to a face plate using various methods. In some embodiments, a scoreline profile can be formed on the outer impact surface of a cover layer with a mold. For example, a selected scoreline profile can be etched, machined, or otherwise transferred to the mold surface. The mold can be used to form a cover layer having an impact surface that includes the scoreline profile, which can then be attached to a composite face plate or face plate comprised of other materials. Such cover layers can be bonded with an adhesive to the face plate.
Alternatively, a mold can be used to form the cover layer directly on the composite face plate. For example, a layer of a thermoplastic material (or pellets or other portions of such a material) can be placed on an external surface of a pre-formed face plate, and the assembly can be placed in a mold. The mold has a surface with the desired scoreline profile adjacent the polymeric material. The mold surfaces can be pressed against the thermoplastic material and the face plate at suitable temperatures and pressures so as to impress the desired scoreline profile on a thermoplastic layer, thereby forming a cover layer with a desired scoreline profile. In another example, a thermoset material can be deposited on the external surface of the face plate, and the mold pressed against the thermoset material and the face plate to form a cover layer having a desired thickness and scoreline profile. The face plate, the thermoset material, and the mold can then be raised to a suitable temperature so as to cure or otherwise fix the shape and thickness of the cover layer. Exemplary materials are described above.
In other embodiments, a composite face plate and cover layer can be formed at the same time in a mold. For example, a lay-up can be formed from a plurality of pre-preg composite sheets (as disclosed in U.S. Pat. No. 7,874,936) and a layer of polymeric material to form the cover layer of the face plate. The lay-up can be placed in a mold, which applies heat and/or pressure to the lay-up to form a molded part. The cured, molded part can then be removed from the mold and machined as needed to achieve the final shape and size of the face plate. These methods are examples only, and other methods can be used as may be convenient for forming cover layers for face plates.
In other embodiments, the desired scoreline profile can be machined or otherwise formed directly on the face plate. For example, a desired scoreline profile can be machined directly into a metal (e.g., titanium) face plate.
In one embodiment, the total mass of the golf club head is between 185 g and 215 g, or between 190 g and 210, or between 194 g and 205 g. In other embodiments, the total mass of the golf club head is between 165 g and 185 g. In similar embodiments, the volume of the golf club head as measured according to the USGA rules is between 390 cc and 475 cc, or between 410 cc and 470 cc, or greater than 400 cc. In certain embodiments, the coefficient of restitution is greater than 0.80 or 0.81, or between about 0.81 and 0.83, as measured according to the USGA rules of golf. In addition, in some embodiments, the characteristic time is greater than 230 μs, or 220 μs, or 210 μs, or between about 230 μs and 257 μs, as measured according to the USGA rules.
In the embodiments described herein, the “face size” or “striking surface area” is defined according to a specific procedure described herein. A front wall extended surface is first defined which is the external face surface that is extended outward (extrapolated) using the average bulge radius (heel-to-toe) and average roll radius (crown-to-sole). The bulge radius is calculated using five equidistant points of measurement fitted across a 2.5 inch segment along the x-axis (symmetric about the center point). The roll radius is calculated by three equidistant points fitted across a 1.5 inch segment along the y-axis (also symmetric about the center point).
The front wall extended surface is then offset by a distance of 0.5 mm towards the center of the head in a direction along an axis that is parallel to the face surface normal vector at the center of the face. The center of the face is defined according to USGA “Procedure for Measuring the Flexibility of a Golf Clubhead”, Revision 2.0, Mar. 25, 2005.
In certain embodiments, the striking surface has a surface area between about 4,000 mm2 and 6,200 mm2 and, in certain preferred embodiments, the striking surface is at least about 5,000 mm2 or between about 5,000 mm2 and 5,500 mm2.
In order to achieve the desired face size, mass is removed from the crown material so that the crown material is between about 0.4 mm and 0.8 mm or less than 0.7 mm over at least 50% of the crown surface area.
In some embodiments, the golf club head can have a CG with a CG x-axis coordinate between about −5 mm and about 10 mm, a CG y-axis coordinate between about 15 mm and about 50 mm, and a CG z-axis coordinate between about −10 mm and about 5 mm. In yet another embodiment, the CG y-axis coordinate is between about 20 mm and about 50 mm. A positive CG y-axis is in a rearward direction of the club head, a positive CG x-axis is in a heel-ward direction of the club head, and a positive CG z-axis is in an upward or crown-ward direction on the club head.
The CG locations described are relative to a head origin coordinate system being provided such that the location of various features of the club head can be determined. The club head origin point is positioned at the geometric center of the striking surface which can be the location of ideal impact.
In certain embodiments, the club head height is between about 63.5 mm to 71 mm (2.5″ to 2.8″) and the width is between about 116.84 mm to about 127 mm (4.6″ to 5.0″). Furthermore, the depth dimension is between about 111.76 mm to about 127 mm (4.4″ to 5.0″). The club head height, width, and depth are measured according to the USGA rules. In similar embodiments, the moment of inertia about the CG x-axis (toe to heel), the CG y-axis (back to front), and CG z-axis (sole to crown) is defined. In certain implementations, the club head can have a moment of inertia about the CG z-axis, between about 450 kg·mm2 and about 650 kg·mm2, and a moment of inertia about the CG x-axis between about 300 kg·mm2 and about 500 kg·mm2, and a moment of inertia about the CG y-axis between about 300 kg·mm2 and about 500 kg·mm2. In certain other implementations, the club head can have a moment of inertia about the CG z-axis between about 320 kg·mm2 and about 450 kg·mm2, and a moment of inertia about the CG x-axis between about 190 kg·mm2 and about 350 kg·mm2, and a moment of inertia about the CG y-axis between about 250 kg·mm2 and about 350 kg·mm2.
Whereas the invention has been described in connection with representative embodiments, it will be understood that the invention is not limited to those embodiments. On the contrary, the invention is intended to encompass all modifications, alternatives, and equivalents as may fall within the scope of the invention, as defined by the following claims.
Claims
1. A wood-type golf club head comprising:
- a body having a crown, a sole, a heel, and a toe, the body defining an internal cavity having a front opening;
- a striking plate attached to the body at the front opening, the striking plate comprising: a composite face plate having a front surface, and a cover layer attached to the front surface of the face plate, the cover layer defining a forward facing striking surface having a plurality of scorelines, each such scoreline having a scoreline depth of at least 0.1 mm, a peripheral edge, a center zone that is defined by an outer border constituting a center zone circle having a diameter Dcz, with the center of the center zone circle corresponding with a USGA center face location, an impact zone that surrounds but does not include the center zone and that is defined by an outer border constituting a rectangle having its center at the USGA center face location and having upper and lower sides aligned parallel to an address position ground plane and heel and toe sides aligned perpendicular to the address position ground plane, with the upper and lower sides each having a length of 45 mm and the heel and toe sides each having a length of 30 mm, and with the impact zone having an impact zone area, Aiz, and a peripheral zone that surrounds but does not include the impact zone and that extends to the peripheral edge, with the peripheral zone having a peripheral zone area, Apz;
- wherein: the club head defines a striking surface area of at least 4,000 mm2, and the center zone circle diameter Dcz is between 1 mm to 10 mm,
- wherein the portion of the cover layer within the center zone of the striking plate does not include any scorelines;
- wherein the impact zone is provided with a plurality of scorelines having a scoreline area, Asliz, such that the ratio Asliz/Aiz is at least 0.17; and
- wherein each of the scorelines outside the center zone extends across substantially the full width of the striking surface.
2. The golf club head of claim 1, wherein the impact zone is provided with a plurality of scorelines having a scoreline area, Asliz, such that the ratio Asliz/Aiz is at least 0.20.
3. The golf club head of claim 1, wherein the center zone circle diameter Dcz is between 3 mm to 8 mm.
4. The golf club head of claim 1, wherein the center zone circle diameter Dcz is between 3 mm to 6 mm.
5. The golf club head of claim 1, wherein the club head defines a striking surface area of at least 5,000 mm2.
6. The golf club head of claim 1, wherein the peripheral zone is provided with a plurality of scorelines having a scoreline area, Aslpz, such that the ratio Aslpz/Apz is at least 0.10.
7. The golf club head of claim 1, wherein the peripheral zone is provided with a plurality of scorelines having a scoreline area, Aslpz, such that the ratio Aslpz/Apz is at least 0.17.
8. The golf club head of claim 1, wherein the peripheral zone is provided with a plurality of scorelines having a scoreline area, Aslpz, such that the ratio Aslpz/Apz is at least 0.20.
9. The golf club head of claim 1, wherein the cover layer has an average thickness of between 0.2 mm to 0.75 mm throughout at least the center zone and impact zone, and the plurality of scorelines in the impact zone have an average depth that is between 0.1 mm and 0.4 mm.
10. The golf club head of claim 1, wherein a ratio of the average depth of the plurality of scorelines in the impact zone to the average thickness of the cover layer in the impact zone is between 0.2 to 0.9.
11. The golf club head of claim 1, wherein a ratio of the average depth of the plurality of scorelines in the impact zone to the average thickness of the cover layer in the impact zone is between 0.5 to 0.8.
12. The golf club head of claim 1, wherein a ratio of the average depth of the plurality of scorelines in the impact zone to the average thickness of the cover layer in the impact zone is between 0.6 to 0.8.
13. The golf club head of claim 1, wherein a volume of the golf club head is between 390 cc and 475 cc.
14. The golf club head of claim 1, wherein a volume of the golf club head is greater than 400 cc.
15. The golf club head of claim 1, wherein a ratio of the scoreline width to the width of the land area between adjacent scorelines is between 1:3 and 1:5 for at least 50% of the scorelines in the impact zone.
16. The golf club head of claim 1, wherein a ratio of the scoreline width to the width of the land area between adjacent scorelines is between 1:3 and 1:5 for at least 75% of the scorelines in the impact zone.
17. The golf club head of claim 1, wherein a ratio of the scoreline width to the width of the land area between adjacent scorelines is between 1:3 and 1:4 for at least 50% of the scorelines in the impact zone.
18. The golf club head of claim 1, wherein a ratio of the scoreline width to the width of the land area between adjacent scorelines is between 1:3 and 1:4 for at least 75% of the scorelines in the impact zone.
19. The golf club head of claim 1, wherein a ratio of the scoreline width to the width of the land area between adjacent scorelines is between 1:3 and 1:5 for at least 50% of the scorelines in the peripheral zone.
20. A wood-type golf club head comprising:
- a body having a crown, a sole, a heel, and a toe, the body defining an internal cavity having a front opening;
- a striking plate attached to the body at the front opening, the striking plate comprising: a composite face plate having a front surface, and a cover layer attached to the front surface of the face plate, the cover layer defining a forward facing striking surface having a plurality of scorelines, each such scoreline having a scoreline depth of at least 0.1 mm, a peripheral edge, a center zone that is defined by an outer border constituting a center zone circle having a diameter Dcz, with the center of the center zone circle corresponding with a USGA center face location, an impact zone that surrounds but does not include the center zone and that is defined by an outer border constituting a rectangle having its center at the USGA center face location and having upper and lower sides aligned parallel to an address position ground plane and heel and toe sides aligned perpendicular to the address position ground plane, with the upper and lower sides each having a length of 45 mm and the heel and toe sides each having a length of 30 mm, and with the impact zone having an impact zone area, Aiz, and a peripheral zone that surrounds but does not include the impact zone and that extends to the peripheral edge, with the peripheral zone having a peripheral zone area, Apz;
- wherein: the club head defines a striking surface area of at least 4,000 mm2, and the center zone circle diameter Dcz is between 1 mm to 10 mm,
- wherein the portion of the cover layer within the center zone of the striking plate does not include any scorelines;
- wherein the impact zone is provided with a plurality of scorelines having a scoreline area, Asliz, such that the ratio Asliz/Aiz is at least 0.17; and
- wherein the scorelines additionally comprise a width of at least 0.6 mm, and a uniform scoreline spacing of less than 3 mm such that the impact zone comprises at least 10 scorelines.
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Type: Grant
Filed: Dec 27, 2012
Date of Patent: Nov 3, 2015
Patent Publication Number: 20130190102
Assignee: Taylor Made Golf Company, Inc. (Carlsbad, CA)
Inventors: Mark Vincent Greaney (Vista, CA), John Francis Lorentzen (El Cajon, CA), Bing-Ling Chao (San Diego, CA), Todd P. Beach (San Diego, CA)
Primary Examiner: Gene Kim
Assistant Examiner: Matthew B Stanczak
Application Number: 13/728,683
International Classification: A63B 53/00 (20150101); A63B 53/04 (20150101);
